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*** 0 ****
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+
+
+
+ SFIO(3) SFIO(3)
+
+
+ NNAAMMEE
+ ssffiioo - safe/fast string/file input/output
+
+ SSYYNNOOPPSSIISS
+ #include <sfio.h>
+
+ DDAATTAA TTYYPPEESS
+ Void_t;
+ Sfoff_t;
+ Sflong_t;
+ Sfulong_t;
+ Sfdouble_t;
+
+ Sfio_t;
+
+ Sfdisc_t;
+ ssize_t (*Sfread_f)(Sfio_t*, Void_t*, size_t, Sfdisc_t*);
+ ssize_t (*Sfwrite_f)(Sfio_t*, const Void_t*, size_t, Sfdisc_t*);
+ Sfoff_t (*Sfseek_f)(Sfio_t*, Sfoff_t, int, Sfdisc_t*);
+ int (*Sfexcept_f)(Sfio_t*, int, Void_t*, Sfdisc_t*);
+
+ Sffmt_t;
+ int (*Sffmtext_f)(Sfio_t*, Void_t*, Sffmt_t*);
+ int (*Sffmtevent_f)(Sfio_t*, int, Void_t*, Sffmt_t*);
+
+ SFIO_VERSION
+
+ BBIITT FFLLAAGGSS
+ SF_STRING
+ SF_READ
+ SF_WRITE
+ SF_APPEND
+ SF_LINE
+ SF_SHARE
+ SF_PUBLIC
+ SF_MALLOC
+ SF_STATIC
+ SF_IOCHECK
+ SF_BUFCONST
+ SF_WHOLE
+
+ OOPPEENNIINNGG//CCLLOOSSIINNGG SSTTRREEAAMMSS
+ Sfio_t* sfnew(Sfio_t* f, Void_t* buf, size_t size, int fd, int flags);
+ Sfio_t* sfopen(Sfio_t* f, const char* string, const char* mode);
+ Sfio_t* sfpopen(Sfio_t* f, const char* cmd, const char* mode);
+ Sfio_t* sftmp(size_t size);
+ int sfclose(Sfio_t* f);
+
+ IINNPPUUTT//OOUUTTPPUUTT OOPPEERRAATTIIOONNSS
+ int sfgetc(Sfio_t* f);
+ int sfputc(Sfio_t* f, int c);
+ int sfnputc(Sfio_t* f, int c, int n);
+ int sfungetc(Sfio_t* f, int c);
+
+
+
+
+ 05 August 1999 1
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ Sfulong_t sfgetu(Sfio_t* f);
+ int sfputu(Sfio_t* f, Sfulong_t v);
+ Sflong_t sfgetl(Sfio_t* f);
+ int sfputl(Sfio_t* f, Sflong_t v);
+ Sfdouble_t sfgetd(Sfio_t* f);
+ int sfputd(Sfio_t* f, Sfdouble_t v);
+
+ char* sfgetr(Sfio_t* f, int rsc, int type);
+ ssize_t sfputr(Sfio_t* f, const char* s, int rsc);
+ Sfoff_t sfmove(Sfio_t* fr, Sfio_t* fw, Sfoff_t n, int rsc);
+
+ ssize_t sfread(Sfio_t* f, Void_t* buf, size_t n);
+ ssize_t sfwrite(Sfio_t* f, const Void_t* buf, size_t n);
+ Sfoff_t sfseek(Sfio_t* f, Sfoff_t offset, int type);
+ Void_t* sfreserve(Sfio_t* f, ssize_t n, int lock);
+
+ DDAATTAA FFOORRMMAATTTTIINNGG
+ int sfscanf(Sfio_t* f, const char* format, ...);
+ int sfsscanf(const char* s, const char* format, ...);
+ int sfvsscanf(const char* s, const char* format, va_list args);
+ int sfvscanf(Sfio_t* f, const char* format, va_list args);
+
+ int sfprintf(Sfio_t* f, const char* format, ...);
+ char* sfprints(const char* format, ...);
+ int sfsprintf(char* s, int n, const char* format, ...);
+ int sfvsprintf(char* s, int n, const char* format, va_list args);
+ int sfvprintf(Sfio_t* f, const char* format, va_list args);
+
+ Sffmt_t;
+ int (*Sffmtext_f)(Sfio_t* f, Void_t* v, Sffmt_t* fe);
+ int (*Sffmtevent_f)(Sfio_t* f, int type, Void_t* v, Sffmt_t* fe);
+ void va_copy(va_list to, va_list fr);
+ long sffmtversion(Sffmt_t* fe, type);
+
+ BBUUFFFFEERRIINNGG,, SSYYNNCCHHRROONNIIZZAATTIIOONN
+ Void_t* sfsetbuf(Sfio_t* f, Void_t* buf, size_t size);
+ int sfsync(Sfio_t* f);
+ int sfpoll(Sfio_t** flist, int n, int timeout);
+ Sfio_t* sfpool(Sfio_t* f, Sfio_t* poolf, int mode);
+ int sfpurge(Sfio_t* f);
+
+ DDIISSCCIIPPLLIINNEE,, EEVVEENNTT HHAANNDDLLIINNGG
+ Sfdisc_t* sfdisc(Sfio_t* f, Sfdisc_t* disc);
+ int sfraise(Sfio_t* f, int type, Void_t* data);
+ ssize_t sfrd(Sfio_t* f, Void_t* buf, size_t n, Sfdisc_t* disc);
+ ssize_t sfwr(Sfio_t* f, const Void_t* buf, size_t n, Sfdisc_t* disc);
+ Sfoff_t sfsk(Sfio_t* f, Sfoff_t offset, int type, Sfdisc_t* disc);
+
+ SSTTRREEAAMM CCOONNTTRROOLL
+ int sfset(Sfio_t* f, int flags, int i);
+ int sfsetfd(Sfio_t* f, int fd);
+ Sfio_t* sfstack(Sfio_t* base, Sfio_t* top);
+ Sfio_t* sfswap(Sfio_t* f1, Sfio_t* f2);
+
+
+
+
+ 05 August 1999 2
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ SSTTRREEAAMM IINNFFOORRMMAATTIIOONN
+ Sfoff_t sfsize(Sfio_t* f);
+ Sfoff_t sftell(Sfio_t* f);
+ ssize_t sfvalue(Sfio_t* f);
+ int sffileno(Sfio_t* f);
+
+ int sfstacked(Sfio_t* f);
+ int sfeof(Sfio_t* f);
+ int sferror(Sfio_t* f);
+ int sfclrerr(Sfio_t* f);
+ int sfclrlock(Sfio_t* f);
+
+ int sfnotify(void (*notify)(Sfio_t* f, int type, int fd));
+
+ MMIISSCCEELLLLAANNEEOOUUSS FFUUNNCCTTIIOONNSS
+ ssize_t sfslen();
+ int sfulen(Sfulong_t v);
+ int sfllen(Sflong_t v);
+ int sfdlen(Sfdouble_t v);
+ ssize_t sfpkrd(int fd, Void_t* buf, size_t n,
+ int rsc, long tm, int peek);
+
+ FFUULLLL SSTTRRUUCCTTUURREE SSFFIIOO__TT
+ #include <sfio_t.h>
+ #define SFNEW(buf,size,file,flags,disc)
+
+ EEXXAAMMPPLLEE DDIISSCCIIPPLLIINNEESS
+ int sfdcdio(Sfio_t* f, size_t bufsize);
+ int sfdcdos(Sfio_t* f);
+ int sfdcfilter(Sfio_t* f, const char* cmd);
+ int sfdclzw(Sfio_t* f);
+ int sfdcseekable(Sfio_t* f);
+ int sfdcslow(Sfio_t* f);
+ int sfdcsubstream(Sfio_t* f, Sfio_t* parent,
+ Sfoff_t offset, Sfoff_t extent);
+ int sfdctee(Sfio_t* f, Sfio_t* tee);
+ int sfdcunion(Sfio_t* f, Sfio_t** array, int n);
+
+ SSTTDDIIOO--CCOOMMPPAATTIIBBIILLIITTYY
+ #include <stdio.h>
+ cc ... -lstdio -lsfio
+
+ DDEESSCCRRIIPPTTIIOONN
+ Sfio is a library of I/O functions to manage buffered
+ streams. Each Sfio stream is a _f_i_l_e _s_t_r_e_a_m, representing
+ a file (see open(2)), or a _s_t_r_i_n_g _s_t_r_e_a_m, representing a
+ memory segment. Beyond the usual I/O operations on
+ streams, Sfio provides I/O disciplines for extended data
+ processing, stream stacks for recursive stream processing,
+ and stream pools for automatic data synchronization. The
+ sfprintf()/sfscanf() functions allow applications to
+ define their own formatting patterns as well as to rede-
+ fine existing patterns.
+
+
+
+
+ 05 August 1999 3
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ A discipline defines analogues of the system calls
+ read(2), write(2) and lseek(2). Such system calls or
+ their discipline replacements are used to process stream
+ data. Henceforth, ``_s_y_s_t_e_m _c_a_l_l'' will mean a system call
+ or its discipline replacement.
+
+ A system call is said to cause an exception if its return
+ value is non-positive. Unless overridden by exception
+ handlers (see sfdisc()), an interrupted system call (errno
+ == EINTR on UNIX systems) will be automatically reinvoked
+ to continue the ongoing operation.
+
+ The buffer of a stream is typically a memory segment allo-
+ cated via malloc(3) or supplied by the application. File
+ streams may also use memory mapping (mmap(2)) if that is
+ more efficient. When memory mapping is used, the underly-
+ ing file should not be truncated while the stream is
+ active. Memory mapping can be turned off using sfset-
+ buf().
+
+ There are three _s_t_a_n_d_a_r_d _s_t_r_e_a_m_s: sfstdin for input (file
+ descriptor 0 on UNIX systems), sfstdout for normal output
+ (file descriptor 1), and sfstderr for error output (file
+ descriptor 2).
+
+
+
+ DDAATTAA TTYYPPEESS
+ VVooiidd__tt**
+ This defines a type suitable to exchange data of unknown
+ types between application and Sfio. Void_t is a macro
+ defined as void for ANSI-C and C++ and char for other com-
+ pilation environments.
+
+
+ SSffooffff__tt
+ This defines an integral type suitable to address the
+ largest possible file extent.
+
+
+ SSffuulloonngg__tt,, SSfflloonngg__tt,, SSffddoouubbllee__tt
+ These are respectively the largest unsigned integer,
+ signed integer, and floating point value types on the
+ local platform.
+
+
+ SSffiioo__tt
+ This defines the stream type.
+
+
+ SSffddiisscc__tt
+ ssssiizzee__tt ((**SSffrreeaadd__ff))((SSffiioo__tt**,, VVooiidd__tt**,, ssiizzee__tt,, SSffddiisscc__tt**))
+
+
+
+
+
+ 05 August 1999 4
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ ssssiizzee__tt ((**SSffwwrriittee__ff))((SSffiioo__tt**,, ccoonnsstt VVooiidd__tt**,, ssiizzee__tt,,
+ SSffddiisscc__tt**))
+ SSffooffff__tt ((**SSffsseeeekk__ff))((SSffiioo__tt**,, SSffooffff__tt,, iinntt,, SSffddiisscc__tt**))
+ iinntt ((**SSffeexxcceepptt__ff))((SSffiioo__tt**,, iinntt,, VVooiidd__tt**,, SSffddiisscc__tt**))
+ Sfdisc_t defines a stream discipline structure. Sfread_f,
+ Sfwrite_f and Sfseek_f are the types of discipline func-
+ tions to replace the system calls: read(2), write(2) and
+ lseek(2). Sfexcept_f is the type of an event-handling
+ function. See sfdisc() for more details.
+
+
+ SSffffmmtt__tt
+ iinntt ((**SSffffmmtteexxtt__ff))((SSffiioo__tt**,, VVooiidd__tt**,, SSffffmmtt__tt**))
+ iinntt ((**SSffffmmtteevveenntt__ff))((SSffiioo__tt**,, iinntt,, VVooiidd__tt**,, SSffffmmtt__tt**))
+ Sffmt_t defines a formatting environment that can be used
+ to extend scanning and formatting in the sfprint()/sfs-
+ canf() functions. Sffmtext_f and Sffmtevent_f define the
+ types of extension functions definable in Sffmt_t. See
+ Sffmt_t below for more details.
+
+
+ SSFFIIOO__VVEERRSSIIOONN
+ This is a macro value of type long int that defines the
+ current version number of Sfio. For example, the
+ Sfio1998's version number is 19980501L (which also indi-
+ cates its release date).
+
+
+ BBIITT FFLLAAGGSS
+ A number of bit flags control stream operations. They are
+ set either at stream initialization or by calling sfset().
+ Following are the flags:
+
+ SF_STRING:
+ The stream is memory-based.
+
+ SF_READ, SF_WRITE, SF_APPEND:
+ Flags SF_READ and SF_WRITE indicate readability and
+ writability. Flag SF_APPEND asserts that the
+ stream is a file opened in append mode (see open(2)
+ and fcntl(2)) so that data is always output at the
+ end of file. On systems without direct support for
+ append mode, Sfio uses lseek(2) or its discipline
+ replacement to approximate this behavior.
+
+ SF_LINE:
+ The stream is line-oriented. For a SF_WRITE
+ stream, this means that buffered data is flushed
+ whenever a new-line character, \n, is output. For
+ a SF_READ stream, SF_LINE is only significant dur-
+ ing calls to functions in the sfscanf() family.
+ SF_LINE is set on initialization of any stream rep-
+ resenting a terminal device.
+
+
+
+
+ 05 August 1999 5
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ SF_SHARE, SF_PUBLIC:
+ Flag SF_SHARE means that the underlying file
+ descriptor is shared by independent entities (for
+ example, multiple processes).
+
+ For a seekable file stream, SF_SHARE means that the
+ logical stream and the physical file positions will
+ be made the same before a system call to perform
+ physical I/O. There are different possibilities.
+ If SF_PUBLIC is not set, the physical file position
+ is made equal to the logical stream position. If
+ SF_PUBLIC is set, there are two cases. If the
+ physical file position has changed from its last
+ known position, the logical stream position is made
+ equal to the new physical file position. Finally,
+ if the physical file location remains the same as
+ its last known position, the physical file position
+ is made the same as the logical stream position.
+
+ For an unseekable stream (e.g., pipes or terminal
+ devices), if possible, SF_SHARE means that the
+ block and record I/O operations (sfread(),
+ sfwrite(), sfmove(), sfgetr(), sfputr(), sfre-
+ serve(), sfscanf() and sfvprintf()) will ensure:
+ (1) after each writing operation, the stream is
+ synchronized and (2) each reading operation only
+ reads the requested amount. Note, however, that
+ (2) is not always possible without proper OS facil-
+ ities such as recv(2) or streamio(4).
+
+ A standard stream that is seekable will be initial-
+ ized with SF_SHARE|SF_PUBLIC.
+
+ SF_MALLOC:
+ The stream buffer was obtained via malloc(3) and
+ can be reallocated or freed.
+
+ SF_STATIC:
+ The stream structure should not be freed when
+ closed (sfclose()). This flag is used by an appli-
+ cations that allocate their own stream structures.
+ Such applications must use the header file sfio_t.h
+ instead of sfio.h.
+
+ SF_IOCHECK:
+ If the stream has a discipline exception handler,
+ exceptions will be raised in sfsync(), sfpurge() or
+ before a system call read(2) or write(2) (see
+ sfdisc()).
+
+ SF_BUFCONST:
+ The application guarantees that a stream buffer
+ obtained via sfreserve() or sfgetr() will not be
+ modified. This allows Sfio to tune buffer
+
+
+
+ 05 August 1999 6
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ management and memory maps. For example, a memory-
+ mapped stream will map with MAP_SHARED on and
+ PROT_WRITE off so that the file itself will likely
+ be the backing store for mapped pages.
+
+ SF_WHOLE:
+ This flag guarantees that data written in any sin-
+ gle sfwrite() or sfputr() call will always be out-
+ put as a whole to the output device. This is use-
+ ful in certain applications (e.g., networking)
+ where a complex object must be output without being
+ split in different system calls. Note that the
+ respective stream still buffers data as the buffer
+ can accomodate.
+
+
+
+ OOPPEENNIINNGG//CCLLOOSSIINNGG SSTTRREEAAMMSS
+ SSffiioo__tt** ssffnneeww((SSffiioo__tt** ff,, VVooiidd__tt** bbuuff,, ssiizzee__tt ssiizzee,, iinntt ffdd,,
+ iinntt ffllaaggss))
+ This function creates or renews a stream. It returns the
+ new stream on success and NULL on error.
+
+ f: If f is NULL, a new stream is created. Otherwise,
+ f is reused. In this case, if flags does not have
+ SF_EOF, f shall be closed via sfclose() before
+ being reused. During a stream renewal, buffer,
+ pool and discipline stack are preserved. Note
+ that, except for SF_STATIC streams, renewing a
+ stream already closed will result in undefined
+ behavior.
+
+ buf, size:
+ These determine a buffering scheme. See sfsetbuf()
+ for more details.
+
+ fd: If SF_STRING is specified in flags, this is
+ ignored. Otherwise, fd is a file descriptor (e.g.,
+ from open(2)) to use for raw data I/O. Note that
+ Sfio supports unseekable file descriptors opened
+ for both read and write, e.g., sockets.
+
+ flags: This is composed from SF_EOF and bit values defined
+ in the BBIITT FFLLAAGGSS section.
+
+
+ SSffiioo__tt** ssffooppeenn((SSffiioo__tt** ff,, ccoonnsstt cchhaarr** ssttrriinngg,, ccoonnsstt cchhaarr**
+ mmooddee))
+ If string is NULL and f is a file stream that has not per-
+ formed any I/O operation, sfopen() will change the modes
+ of f according to mode. In this case, sfopen() returns f
+ on success and NULL on error. This somewhat unusual usage
+ of sfopen() is good for changing the predefined modes of
+ standard streams.
+
+
+
+ 05 August 1999 7
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ sfopen() is normally used to create a new stream or renew
+ a stream. In this case, it returns the new stream on suc-
+ cess and NULL on error. Below are the meanings of the
+ arguments:
+
+ f: This is treated as in sfnew().
+
+ string:
+ This is a file name or a string to perform I/O on.
+
+ mode: This is composed from the set of letters {s, r, w,
+ +, a, x, b, t}.
+
+ s specifies opening a string stream. string can be
+ a null-terminated string or NULL. Specifying s
+ alone is equivalent to specifying sr. If s is not
+ specified, string defines a file name.
+
+ r and w specify read and write modes. Write mode
+ creates and/or truncates the given file to make an
+ empty file. The + modifier indicates that the
+ stream is opened for both read and write.
+
+ a specifies append mode, i.e., data is always out-
+ put at end of file.
+
+ x specifies exclusive mode, i.e., a file opened for
+ writing should not already exist.
+
+ b and t specify binary and text modes.
+
+
+ SSffiioo__tt** ssffppooppeenn((SSffiioo__tt** ff,, ccoonnsstt cchhaarr** ccmmdd,, ccoonnsstt cchhaarr**
+ mmooddee))
+ This function opens a stream that corresponds to the
+ coprocess cmd. The argument mode should be composed from
+ r, w, and +. The argument f, if not NULL, is a stream to
+ be renewed (see sfnew()). sfpopen() returns the new
+ stream or NULL on error.
+
+ The standard input/output of cmd is connected to the
+ application via a pipe if the stream is opened for writ-
+ ing/reading. If the stream is opened for both reading and
+ writing, there will be two different associated file
+ descriptors, one for each type of I/O (note the effect on
+ sffileno()).
+
+ On opening a coprocess for writing (i.e., mode contains w
+ or +), the signal handler for SIGPIPE in the parent appli-
+ cation will be set to SIG_IGN if it is SIG_DFL at that
+ time. This protects the parent application from being
+ accidentally killed on any attempt to write to a coprocess
+ that closes its reading end. Applications that need to
+ detect such write errors should use disciplines and
+
+
+
+ 05 August 1999 8
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ exception handlers (see sfdisc()).
+
+ The command cmd is executed by an _i_n_t_e_r_p_r_e_t_e_r which is
+ either /bin/sh or an executable command defined by the
+ environment variable SHELL. In either case, the inter-
+ preter is invoked with 2 arguments, respectively -c and
+ the given command cmd. When the interpreter is /bin/sh or
+ /bin/ksh, sfpopen() may execute the command cmd itself if
+ there are no shell meta-characters in cmd.
+
+
+ SSffiioo__tt** ssffttmmpp((ssiizzee__tt ssiizzee))
+ This function creates a stream for temporary data. It
+ returns the new stream or NULL on error.
+
+ A stream created by sftmp() can be completely or partially
+ memory-resident. If size is SF_UNBOUND, the stream is a
+ pure string stream. If size is zero, the stream is a pure
+ file stream. Otherwise, the stream is first created as a
+ string stream but when its buffer grows larger than size
+ or on any attempt to change disciplines, a temporary file
+ is created. Two environment variables, TMPPATH and
+ TMPDIR, direct where temporary files are created. TMP-
+ PATH, if defined, specifies a colon-separated set of
+ directories to be used in a round-robin fashion to create
+ files. If TMPPATH is undefined, TMPDIR can be used to
+ specify a single directory to create files. If neither of
+ TMPPATH and TMPDIR are defined, /tmp is used.
+
+
+ iinntt ssffcclloossee((SSffiioo__tt** ff))
+ This function closes the stream f and frees its resources.
+ SF_STATIC should be used if the stream space is to be pre-
+ served. If f is the base of a stream stack (see sfs-
+ tack()), all streams on the stack are closed. If f is a
+ sfpopen-stream, sfclose() waits until the associated com-
+ mand terminates and returns its exit status. sfclose()
+ returns -1 for failure and 0 for success.
+
+ SF_READ|SF_SHARE and SF_WRITE streams are synchronized
+ before closing (see sfsync()). If f has disciplines,
+ their exception handlers will be called twice. The first
+ exception handler call has the type argument as one of
+ SF_CLOSE or SF_NEW (see sfdisc().) The latter, SF_NEW is
+ used when a stream is being closed via sfnew() so that it
+ can be renewed. The second call uses type as SF_FINAL and
+ is done after all closing operations have succeeded but
+ before the stream itself is deallocated. In either case,
+ if the exception handler returns a negative value,
+ sfclose() will immediately return this value. If the
+ exception handler returns a positive value, sfclose() will
+ immediately return a zero value.
+
+
+
+
+
+ 05 August 1999 9
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ IINNPPUUTT//OOUUPPUUTT OOPPEERRAATTIIOONNSS
+ iinntt ssffggeettcc((SSffiioo__tt** ff))
+ iinntt ssffppuuttcc((SSffiioo__tt** ff,, iinntt cc))
+ These functions read/write a byte from/to stream f.
+ sfgetc() returns the byte read or -1 on error. sfputc()
+ returns c on success and -1 on error.
+
+
+ ssssiizzee__tt ssffnnppuuttcc((SSffiioo__tt** ff,, iinntt cc,, ssiizzee__tt nn))
+ This function attempts to write the byte c to f n times.
+ It returns the number of bytes actually written or -1 on
+ failure.
+
+
+ iinntt ssffuunnggeettcc((SSffiioo__tt** ff,, iinntt cc))
+ This function pushes the byte c back into f. If c matches
+ the byte immediately before the current position in
+ buffered data, the current position is simply backed up
+ (note the effect on sftell() and sfseek()). There is no
+ theoretical limit on the number of bytes that can be
+ pushed back into a stream. Pushed back bytes not part of
+ buffered data will be discarded on any operation that
+ implies buffer synchronization. sfungetc() returns c on
+ success and -1 on failure.
+
+
+ SSffuulloonngg__tt ssffggeettuu((SSffiioo__tt** ff))
+ iinntt ssffppuuttuu((SSffiioo__tt** ff,, SSffuulloonngg__tt vv))
+ These functions read and write Sfulong_t values in a com-
+ pact variable-length portable format. Portability across
+ a write architecture and a read architecture requires that
+ the bit order in a byte is the same on both architectures
+ and the written value is storable in an Sfulong_t on the
+ read architecture. sfgetu() returns the value read or -1
+ on error. sfputu() returns the number of bytes written or
+ -1 on error. See also sfulen().
+
+
+ SSfflloonngg__tt ssffggeettll((SSffiioo__tt** ff))
+ iinntt ssffppuuttll((SSffiioo__tt** ff,, SSfflloonngg__tt vv))
+ These functions are similar to sfgetu() and sfputu() but
+ for reading and writing (signed) Sflong_t values. See
+ also sfllen().
+
+
+ SSffddoouubbllee__tt ssffggeettdd((SSffiioo__tt** ff))
+ iinntt ssffppuuttdd((SSffiioo__tt** ff,, SSffddoouubbllee__tt vv))
+ These functions read and write Sfdouble_t values. In this
+ case, portability depends on the input and output archi-
+ tectures having the same floating point value representa-
+ tion. Values are coded and decoded using ldexp(3) and
+ frexp(3) so they are constrained to the sizes supported by
+ these functions. See also sfdlen().
+
+
+
+
+ 05 August 1999 10
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ cchhaarr** ssffggeettrr((SSffiioo__tt** ff,, iinntt rrsscc,, iinntt ttyyppee))
+ This function reads a record of data ending in the record
+ separator rsc. After sfgetr() returns, the length of the
+ record even if it is incomplete can be retrieved with
+ sfvalue(). sfgetr() returns the record on success and
+ NULL on error.
+
+ The type argument is composed of some subset of the below
+ bit flags:
+
+ SF_STRING:
+ A null byte will replace the record separator to
+ make the record into a C string. Otherwise, the
+ record separator is left alone.
+
+ SF_LOCKR:
+ Upon successfully obtaining a record r, the stream
+ will be locked from further access until it is
+ released with a call sfread(f,r,0).
+
+ SF_LASTR:
+ This should be used only after a failed sfgetr() to
+ retrieve the last incomplete record. In this case,
+ rsc is ignored.
+
+
+ ssssiizzee__tt ssffppuuttrr((SSffiioo__tt** ff,, ccoonnsstt cchhaarr** ss,, iinntt rrsscc))
+ This function writes the null-terminated string s to f.
+ If rsc is non-negative, (unsigned char)rsc is output after
+ the string. sfputr() returns the number of bytes written
+ or -1 on failure.
+
+
+ SSffooffff__tt ssffmmoovvee((SSffiioo__tt** ffrr,, SSffiioo__tt** ffww,, SSffooffff__tt nn,, iinntt rrsscc))
+ This function moves objects from input stream fr to output
+ stream fw. sfmove() returns the number of objects moved
+ or -1 on failure.
+
+ An object is either a byte or a record. The latter is
+ indicated by a non-negative value for the record separator
+ character rsc. If n is negative, all of fr will be moved.
+ Otherwise, n indicates the number of objects to move. If
+ either fr or fw is NULL, it acts as if it is a stream cor-
+ responding to /dev/null, the UNIX device that has no read
+ data and throws away any write data. For example, the
+ call sfmove(f,(Sfio_t*)0,(Sfoff_t)(-1),'\n') simply counts
+ the number of lines in stream f.
+
+
+ ssssiizzee__tt ssffrreeaadd((SSffiioo__tt** ff,, VVooiidd__tt** bbuuff,, ssiizzee__tt nn))
+ This function reads up to n bytes from f into buffer buf.
+ It returns the number of bytes actually read or -1 on
+ error.
+
+
+
+
+ 05 August 1999 11
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ ssssiizzee__tt ssffwwrriittee((SSffiioo__tt** ff,, ccoonnsstt VVooiidd__tt** bbuuff,, ssiizzee__tt nn))
+ This function writes n bytes from buf to f. If f is
+ SF_STRING, and the buffer is not large enough, an SF_WRITE
+ exception shall be raised. sfwrite() returns the number
+ of bytes written or -1 on failure.
+
+
+ SSffooffff__tt ssffsseeeekk((SSffiioo__tt** ff,, SSffooffff__tt ooffffsseett,, iinntt ttyyppee))
+ This function sets a new I/O position for f. It returns
+ the new position or -1 on failure.
+
+ If the stream is a SF_STRING stream and the new address is
+ beyond the current buffer extent, an SF_SEEK exception
+ will be raised (see sfdisc()).
+
+ The new position is determined based on offset and type
+ which is composed from the bit flags:
+
+ 0 or SEEK_SET:
+ offset is the desired position.
+
+ 1 or SEEK_CUR:
+ offset is relative to the current position (see
+ SF_PUBLIC below).
+
+ 2 or SEEK_END:
+ offset is relative to the physical end of file.
+
+ SF_SHARE:
+ The stream is treated as if it has the control bit
+ SF_SHARE on. This implies that a system call seek
+ will be done to ensure that the location seeking to
+ is valid.
+
+ SF_PUBLIC:
+ The stream is treated as if it has the control bit
+ SF_PUBLIC on. If the physical file position has
+ changed from its last known location, the current
+ position is taken as the new physical position.
+ Otherwise, the current position is the logical
+ stream position.
+
+
+ VVooiidd__tt** ssffrreesseerrvvee((SSffiioo__tt** ff,, ssssiizzee__tt nn,, iinntt lloocckk))
+ This function reserves a data block from f. For a SF_READ
+ stream, a data block is a segment of data and for a
+ SF_WRITE stream, it is a buffer suitable for writing. For
+ consistency, a stream opened with SF_READ|SF_WRITE will be
+ treated as if it is a SF_READ stream (see sfset() for set-
+ ting a particular mode.) sfreserve() returns the obtained
+ data block on success and NULL on failure.
+
+ After a sfreserve() call, whether or not it succeeds,
+ sfvalue() can be used to obtain the size of the (may-have-
+
+
+
+ 05 August 1999 12
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ been) available data block.
+
+ n != 0:
+ f will be filled or flushed as necessary to make
+ available a data block of size at least the abso-
+ lute value of n. If this is successful and lock is
+ non-positive, the I/O position will advance by the
+ size of the available data block when n is negative
+ or by exactly n when n is positive. For example,
+ sfreserve(f,-1,0) returns a positive size data
+ block and advances the I/O position by its size.
+ On the other hand, sfreserve(f,1,0) returns a posi-
+ tive size data block and advances the I/O position
+ by exactly 1.
+
+ n == 0:
+ If lock is zero, f will be filled or flushed as
+ necessary to ensure that a positive-size data block
+ is available. If lock is non-zero, no fill or
+ flush will be performed. In addition, if lock is
+ positive, f will be locked from further access.
+ Therefore, an application can lock f with sfre-
+ serve(f,0,1).
+
+ lock: When lock is positive, there are restrictions. If
+ f is SF_READ and not using memory-mapping (see
+ sfsetbuf()), reservation must be limited to stream
+ buffer size. If f is SF_READ|SF_SHARE and unseek-
+ able, sfreserve() will peek at incoming data using
+ either recv(2) or streamio(4) without reading
+ ahead. In this case, if peeking is not supported
+ by the underlying platform, sfreserve() will fail.
+ Note that SF_SHARE is automatically on for sfstdin
+ so programs (e.g., //bbiinn//ssoorrtt) that will consume all
+ of input anyway should turn this bit off to reduce
+ the number of system calls.
+
+ If a reservation successfully results in a data
+ block data, and lock is positive, the stream I/O
+ position does not advance and f will be locked
+ until unlocked with sfread/sfwrite(f,data,size).
+ sfread() should be used on read-only stream and
+ sfwrite() should be used on write-only stream. A
+ stream in both read and write modes can release the
+ lock with either call (with associated operational
+ semantics!)
+
+
+
+ DDAATTAA FFOORRMMAATTTTIINNGG
+ Data printing and scanning are done via the sfprintf() and
+ sfscanf() family of functions. These functions are simi-
+ lar to their ANSI-C fprintf() and fscanf() counterparts.
+ However, the Sfio versions have been extended for both
+
+
+
+ 05 August 1999 13
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ portability and generality. In particular, a notion of a
+ formatting environment stack is introduced. Each format-
+ ting element on the stack defines a separate _f_o_r_m_a_t_t_i_n_g
+ _p_a_i_r of a format specification string, char* format (the
+ usual second argument in the formatting functions), and an
+ argument list, va_list args (the third argument in func-
+ tions sfvprintf() and sfvscanf()). A formatting environ-
+ ment element may also specify extension functions to
+ obtain or assign arguments and to provide new semantics
+ for pattern processing. To simplify the description
+ below, whenever we talk about an argument list, unless
+ noted otherwise, it is understood that this means either
+ the true argument list when there is no extension function
+ or the action to be taken by such a function in processing
+ arguments. The manipulation of the formatting environment
+ stack is done via the pattern ! discussed below.
+
+
+ %%!! aanndd SSffffmmtt__tt
+ The pattern %! manipulates the formatting environment
+ stack to (1) change the top environment to a new environ-
+ ment, (2) stack a new environment on top of the current
+ top, or (3) pop the top environment. The bottom of the
+ environment stack always contains a virtual environment
+ with the original formatting pair and without any exten-
+ sion functions.
+
+ The top environment of a stack, say fe, is automatically
+ popped whenever its format string is completely processed.
+ In this case, its event-handling function (if any) is
+ called as (*eventf)(f,SF_FINAL,NIL(Void_t*),fe). The top
+ environment can also be popped by giving an argument NULL
+ to %! or by returning a negative value in an extension
+ function. In these cases, the event-handling function is
+ called as (*eventf)(f,SF_DPOP,form,fe) where form is the
+ remainder of the format string. A negative return value
+ from the event handling function will prevent the environ-
+ ment from being popped.
+
+ A formatting environment is a structure of type Sffmt_t
+ which contains the following elements:
+
+ Sffmtext_f extf; /* extension processor */
+ Sffmtevent_f eventf; /* event handler */
+
+ char* form; /* format string to stack */
+ va_list args; /* corresponding arg list */
+
+ int fmt; /* pattern being processed */
+ ssize_t size; /* object size */
+ int flags; /* formatting control flags */
+ int width; /* width of field */
+ int precis; /* precision required */
+ int base; /* conversion base */
+
+
+
+ 05 August 1999 14
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ char* t_str; /* type string in parentheses */
+ int n_str; /* length of t_str */
+
+ The first four elements of Sffmt_t must be defined by the
+ application. The two function fields should not be
+ changed during processing. Other elements of Sffmt_t are
+ set on calls to the extension function Sffmt_t.extf and,
+ in turn, can be modified by this function to redirect for-
+ matting or scanning. For example, consider a call from a
+ sfprintf() function to process an unknown pattern %t
+ (which we may take to mean ``time'') based on a formatting
+ environment fe. fe->extf may reset fe->fmt to `d' upon
+ returing to cause sfprintf() to process the value being
+ formatted as an integer.
+
+ Below are the fields of Sffmt_t:
+
+ extf: extf is a function to extend scanning and format-
+ ting patterns. Its usage is discussed below.
+
+ eventf:
+ This is a function to process events as discussed
+ earlier.
+
+ form and args:
+ This is the formatting pair of a specification
+ string and corresponding argument list. When an
+ environment fe is being inserted into the stack, if
+ fe->form is NULL, the top environment is changed to
+ fe and its associated extension functions but pro-
+ cessing of the current formatting pair continues.
+ On the other hand, if fe->form is not NULL, the new
+ environment is pushed onto the stack so that pat-
+ tern processing will start with the new formatting
+ pair as well as any associated extension functions.
+ During processing, whenever extf is called, form
+ and args will be set to the current values of the
+ formatting pair in use.
+
+ fmt: This is the pattern being processed.
+
+ size: This is the size of the object being processed.
+
+ flags: This is a collection of bits defining the format-
+ ting flags specified for the pattern. The bits
+ are:
+
+ SFFMT_LEFT: Flag - in sfprintf().
+
+ SFFMT_SIGN: Flag + in sfprintf().
+
+ SFFMT_BLANK: Flag _s_p_a_c_e in sfprintf().
+
+ SFFMT_ZERO: Flag 0 in sfprintf().
+
+
+
+ 05 August 1999 15
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ SFFMT_THOUSAND: Flag ' in sfprintf().
+
+ SFFMT_LONG: Flag l in sfprintf() and sfscanf().
+
+ SFFMT_LLONG: Flag ll in sfprintf() and sfscanf().
+
+ SFFMT_SHORT: Flag h in sfprintf() and sfscanf().
+
+ SFFMT_LDOUBLE: Flag L in sfprintf() and sfscanf().
+
+ SFFMT_IFLAG: flag I in sfprintf() and sfscanf().
+
+ SFFMT_ALTER: Flag # in sfprintf() and sfscanf().
+
+ SFFMT_SKIP: Flag * in sfscanf().
+
+ SFFMT_ARGPOS: This indicates argument processing
+ for pos$.
+
+ SFFMT_VALUE: This is set by fe->extf to indicate
+ that it is returning a value to be formatted or the
+ address of an object to be assigned.
+
+
+ width: This is the field width.
+
+ precis:
+ This is the precision.
+
+ base: This is the conversion base.
+
+ t_str and n_str:
+ This is the type string and its size.
+
+
+ iinntt ((**SSffffmmtteexxtt__ff))((SSffiioo__tt** ff,, VVooiidd__tt** vv,, SSffffmmtt__tt** ffee))
+ This is the type of the extension function fe->extf to
+ process patterns and arguments. Arguments are always pro-
+ cessed in order and fe->extf is called exactly once per
+ argument. Note that, when pos$ (below) is not used any-
+ where in a format string, each argument is used exactly
+ once per a corresponding pattern. In that case, fe->extf
+ is called as soon as the pattern is recognized and before
+ any scanning or formatting. On the other hand, when pos$
+ is used in a format string, an argument may be used multi-
+ ple times. In this case, all arguments shall be processed
+ in order by calling fe->extf exactly once per argument
+ before any pattern processing. This case is signified by
+ the flag SFFMT_ARGPOS in fe->flags.
+
+ In addition to the predefined formatting patterns and
+ other application-defined patterns, fe->extf may be called
+ with fe->fmt being one of `(' (left parenthesis), `.'
+ (dot), and `I'. The left parenthesis requests a string to
+
+
+
+ 05 August 1999 16
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ be used as the type string discussed below. In this case,
+ upon returning, fe->extf should set the fe->size field to
+ be the length of the string or a negative value to indi-
+ cate a null-terminated string. The dot requests an inte-
+ ger for width, precision, or base. In this case, the
+ fe->size field will indicate how many dots have appeared
+ in the pattern specification. The `I' requests an integer
+ to define the object size.
+
+ f: This is the input/output stream in the calling for-
+ matting function. During a call to fe->extf, the
+ stream shall be unlocked so that fe->extf can read
+ from or write to it as appropriate.
+
+ v: For both sfscanf() and sfprintf() functions, v
+ points to a location suitable for storing any prim-
+ itive data types, i.e., scalars or pointers. On
+ return, fe->extf treats v as discussed below.
+
+ fe: This is the current formatting environment.
+
+ The return value rv of fe->extf directs further process-
+ ing. There are two cases. When pos$ is present, a nega-
+ tive return value means to ignore fe in further argument
+ processing while a non-negative return value is treated as
+ the case rv == 0 below. When pos$ is not present,
+ fe->extf is called per argument immediately before pattern
+ processing and its return values are treated as below:
+
+ rv < 0:
+ The environment stack is immediately popped.
+
+ rv == 0:
+ The extension function has not consumed (in a scan-
+ ning case) or output (in a printing case) data out
+ of or into the given stream f. The fields fmt,
+ flags, size, width, precis and base of fe shall
+ direct further processing.
+
+ For sfprintf() functions, if fe->flags has the bit
+ SFFMT_VALUE, fe->extf should have set *v to the
+ value to be processed; otherwise, a value should be
+ obtained from the argument list. Likewise, for
+ sfscanf() functions, SFFMT_VALUE means that *v
+ should have a suitable address; otherwise, an
+ address to assign value should be obtained from the
+ argument list.
+
+ When pos$ is present, if fe->extf changes fe->fmt,
+ this pattern shall be used regardless of the pat-
+ tern defined in the format string. On the other
+ hand, if fe->fmt is unchanged by fe->extf, the pat-
+ tern in the format string is used. In any case,
+ the effective pattern should be one of the
+
+
+
+ 05 August 1999 17
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ standardly defined pattern. Otherwise, it shall be
+ treated as unmatched.
+
+ rv > 0:
+ The extension function has accessed the stream f to
+ the extent of rv bytes. Processing of the current
+ pattern ceases except that, for scanning functions,
+ if fe->flags does not contain the bit SFFMT_SKIP,
+ the assignment count shall increase by 1.
+
+
+ vvooiidd vvaa__ccooppyy((vvaa__lliisstt ttoo,, vvaa__lliisstt ffrr))
+ This macro function portably copies the argument list fr
+ to the argument list to. It should be used to set the
+ field Sffmt_t.args.
+
+
+ lloonngg ssffffmmttvveerrssiioonn((SSffffmmtt__tt** ffee,, iinntt ttyyppee))
+ This macro function initializes the formatting environment
+ fe with a version number if type is non-zero. Otherwise,
+ it returns the current value of the version number of fe.
+ This is useful for applications to find out when the for-
+ mat of the structure Sffmt_t changes. Note that the ver-
+ sion number corresponds to the Sfio version number which
+ is defined in the macro value SFIO_VERSION.
+
+
+ iinntt ssffpprriinnttff((SSffiioo__tt** ff,, ccoonnsstt cchhaarr** ffoorrmmaatt,, ......))
+ cchhaarr** ssffpprriinnttss((ccoonnsstt cchhaarr** ffoorrmmaatt,, ......))
+ iinntt ssffsspprriinnttff((cchhaarr** ss,, iinntt nn,, ccoonnsstt cchhaarr** ffoorrmmaatt,, ......))
+ iinntt ssffvvsspprriinnttff((cchhaarr** ss,, iinntt nn,, ccoonnsstt cchhaarr** ffoorrmmaatt,, vvaa__lliisstt
+ aarrggss))
+ iinntt ssffvvpprriinnttff((SSffiioo__tt** ff,, ccoonnsstt cchhaarr** ffoorrmmaatt,, vvaa__lliisstt aarrggss))
+ These functions format output data. sfprintf() and
+ sfvprintf() write to output stream f. sfsprintf() and
+ sfvsprintf() write to buffer s which is of size n.
+ sfprints() constructs output in some Sfio-defined buffer.
+ sfvprintf() is the underlying primitive for the other
+ functions. Except for sfprints() which returns a null-
+ terminated string or NULL, other functions return the num-
+ ber of output bytes or -1 on failure.
+
+ The length of string constructed by sfprints(),
+ sfsprintf(), or sfvsprintf() can be retrieved by sfslen().
+
+ The standard patterns are: n, s, c, %, h, i, d, p, u, o,
+ x, X, g, G, e, E, f and !. Except for ! which shall be
+ described below, see the ANSI-C specification of
+ fprintf(3) for details on the other patterns. Let z be
+ some pattern type. A formatting pattern is defined as
+ below:
+
+ %[pos$][flag][width][.precision][.base][(type)]z
+
+
+
+
+ 05 August 1999 18
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ pos$: A pattern can specify which argument in the argu-
+ ment list to use. This is done via pos$ where pos
+ is the argument position. Arguments are numbered
+ so that the first argument after format is at posi-
+ tion 1. If pos is not specified, the argument fol-
+ lowing the most recently used one will be used.
+ The pattern %! (see below) cannot be used subse-
+ quent to a usage of pos$. Doing so may cause unex-
+ pected behaviors.
+
+ flag: The flag characters are h, l, L, I, -, +, _s_p_a_c_e, 0,
+ ' and #.
+
+ Flag I defines the size or type of the object being
+ formatted. There are two cases: (1) I by itself
+ and (2) I followed by either a decimal number or
+ `*'.
+
+ In the first case, for integer and floating point
+ patterns, the object type is taken to be the
+ largest appropriate type (i.e., one of Sflong_t,
+ Sfulong_t or Sfdouble_t). For conversion speci-
+ fiers s and c, the flag is ignored.
+
+ In the second case, a given decimal value would
+ define a size while `*' would cause the size to be
+ obtained from the argument list. Then, if the con-
+ version specifier is s, this size defines the
+ length of the string or strings being formatted
+ (see the discussion of base below). For integer
+ and floating point patterns, the size is used to
+ select a type from one of the below lists as indi-
+ cated by the conversion specifier:
+
+ Sflong_t, long, int, short
+ Sfulong_t, unsigned long, unsigned int, unsigned short
+ Sfdouble_t, double, float
+
+ The selection algorithm always matches types from
+ left to right in any given list. Although selec-
+ tion is generally based on sizes in bytes, for com-
+ patibility with Microsoft-C, the size 64 is matched
+ with an appropriate type with the same number of
+ bits, if any. If the given size does not match any
+ of the listed types, it shall match one of int,
+ unsigned int, and double as defined by the format-
+ ting pattern.
+
+ Below are a few examples of using the I flag. The
+ first example prints an Sflong_t integer. This
+ example is actually not portable and only works on
+ platforms where sizeof(Sflong_t) is 8. The second
+ example shows how to that portably. The third
+ example specifies printing a string of length 16.
+
+
+
+ 05 August 1999 19
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ This length shall be used regardless of whether or
+ not the given string is shorter or longer than 16.
+ The last example shows the use of the pattern %n to
+ assign the amount of data already output into a
+ short integer n_output.
+
+ sfprintf(sfstdout,"%I8d", Sflong_obj);
+ sfprintf(sfstdout,"%I*d", sizeof(Sflong_obj), Sflong_obj);
+ sfprintf(sfstdout,"%I*s", 16, s);
+ sfprintf(sfstdout,"%d%I*n", 1001, sizeof(short), &n_output);
+
+ Flags h, l, and L are the ANSI-C conventions to
+ select the types of input objects. For example,
+ %hd indicates a short int while %ld indicates a
+ long int. The flags ll and L address respectively
+ the largest integer and floating value types, i.e.,
+ Sfulong_t, Sflong_t, and Sfdouble_t.
+
+ Flag - left-justifies data within the field (other-
+ wise, right-justification).
+
+ Flag + means that a signed conversion will always
+ begin with a plus or minus sign.
+
+ Flag _s_p_a_c_e is ignored if + is specified; otherwise,
+ it means that if the first character of a signed
+ conversion is not a sign or if the result is empty,
+ a space will be prepended.
+
+ Flag 0 means padding with zeros on the left.
+
+ Flag ' outputs thousands-separator used by the cur-
+ rent locale. setlocale(3) should have been used to
+ set the desired locale.
+
+ Flag # indicates an alternative format processing.
+ For %o, the first digit is always a zero. For %x
+ and %X, a non-zero result will have a prefix 0x or
+ 0X. For %e, %E, %f, %g, and %G, the result always
+ contains a decimal point. For %g and %G, trailing
+ zeros will not be removed. For %d, %i and %u, the
+ form is _b_a_s_e_#_n_u_m_b_e_r where _b_a_s_e is the conversion
+ base and _n_u_m_b_e_r is represented by digits for this
+ _b_a_s_e. For example, a base 2 conversion with %#..2d
+ for 10 is 2#1010 instead of 1010 as printed with
+ %..2d.
+
+ width: This defines the width of the printing field. A
+ value to be printed will be justified and padded if
+ necessary to fill out the field width.
+
+ precis:
+ After a first dot appears, an integral value
+ defines a precision. For floating point value
+
+
+
+ 05 August 1999 20
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ patterns, precision is the number of precision dig-
+ its. For %c, precision defines the number of times
+ to repeat the character being formatted. For %s,
+ precision defines the maximum number of characters
+ to output.
+
+ base: After a second dot appears, an integral value
+ defines a conversion base.
+
+ For %i, %d, and %u, a conversion base should be in
+ the inclusive range [2,64]. If base is not in this
+ range, it is defined to be 10. The digits to rep-
+ resent numbers are:
+
+ 01234567890
+ abcdefghijklmnopqrstuvwxyz
+ ABCDEFGHIJKLMNOPQRSTUVWXYZ
+ @_
+
+ For %s, when base is defined (i.e., at least two
+ dots appeared in the pattern specification), the
+ input argument is taken as a NULL-terminated list
+ of strings instead of a single string. Each string
+ is formatted based on the usual width and precision
+ rules. If base is non-zero, it defines an ASCII
+ character used to separate the formatted strings.
+ Below is an example showing both the call and the
+ result of printing a NULL-terminated list of three
+ strings apple, orange, and grape:
+
+ sfprintf(sfstdout,"%..*s",',',list);
+ apple,orange,grape
+
+ Likewise, for %c, when base is defined, the input
+ argument is taken as a null-terminated string
+ instead of a single character. Each character is
+ formatted based on the normal width and precision
+ rules. In addition, if base is non-zero, it
+ defines an ASCII character used to separate the
+ formatted characters if there are more than one.
+
+ (str): This defines a string str to be passed to the
+ extension function Sffmt_t.extf. Parentheses shall
+ be balanced. If str is *, the string is obtained
+ from the argument list.
+
+
+
+ iinntt ssffssccaannff((SSffiioo__tt** ff,, ccoonnsstt cchhaarr** ffoorrmmaatt,, ......))
+ iinntt ssffssssccaannff((ccoonnsstt cchhaarr** ss,, ccoonnsstt cchhaarr** ffoorrmmaatt,, ......))
+ iinntt ssffvvssssccaannff((ccoonnsstt cchhaarr** ss,, ccoonnsstt cchhaarr** ffoorrmmaatt,, vvaa__lliisstt
+ aarrggss))
+
+
+
+
+
+ 05 August 1999 21
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ iinntt ssffvvssccaannff((SSffiioo__tt** ff,, ccoonnsstt cchhaarr** ffoorrmmaatt,, vvaa__lliisstt aarrggss))
+ These functions scan data items. sfscanf() scans from the
+ input stream f while sfsscanf() and sfvsscanf() scan from
+ the null-terminated string s. sfvscanf() is the underly-
+ ing primitive that performs the actual scanning. Item
+ types are determined from patterns in string format.
+ These functions return the number of items successfully
+ scanned or -1 on error.
+
+ A white space character (blank, tab, or new-line) in for-
+ mat normally matches a maximal sequence of input white
+ space characters. However, if the input stream is in
+ SF_LINE mode (see sfset()), a new-line character only
+ matches white spaces up to an input new-line character.
+ This is useful to avoid blocking when scanning typed
+ inputs.
+
+ The standard scan patterns are: i, d, u, o, x, X, p, n, f,
+ e, E, g, G, c, %, s, [] and !. Except for ! which shall
+ be described below, see the ANSI-C specification of
+ fscanf(3) for details on other patterns. Let z be some
+ pattern type. A formatting pattern is specified as below:
+
+ %[*][pos$][width][.width.base][(type)][flag]z
+
+
+ pos$: A pattern can specify which argument in the argu-
+ ment list to use. This is done via pos$ where pos
+ is the argument position. Arguments are numbered
+ so that the first argument after format is at posi-
+ tion 1. If pos is not specified, the argument fol-
+ lowing the most recently used one will be used.
+ The pattern %! (see below) cannot be used subse-
+ quent to a usage of pos$.
+
+ *: This discards the corresponding scanned item.
+
+ width and base:
+ width defines the maximum number of bytes to scan
+ and base defines the base of an integral value
+ being scanned. The `.' (dot) notation also allows
+ specifying a `*' (star) to obtain the value from
+ the argument list. The below example specifies
+ scanning 4 bytes to obtain the value of an integer
+ in base 10. At the end of scanning, the variable v
+ should have the value 1234.
+
+ sfsscanf("12345678","%.*.*d", 4, 10, &v);
+
+
+ (str): This defines a string str to be passed to the
+ extension function Sffmt_t.extf. Parentheses shall
+ be balanced. If str is *, the string is obtained
+ from the argument list.
+
+
+
+ 05 August 1999 22
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ flag: This is #, I, or some sequence of h, l, and L.
+
+ Flag # is significant for pattern %i and %[. For
+ %i, it means that the # symbol does not have its
+ usual meaning in an input sequence base#value. For
+ example, the scanning result of %#i on input 2#1001
+ is 2 and the next sfgetc() call will return #. For
+ %[, if the next character in the input stream does
+ not match the given scan set of characters, #
+ causes a match to a null string instead of a fail-
+ ure.
+
+ Flag I defines the size or type of the object being
+ formatted. There are two cases: (1) I by itself
+ and (2) I followed by either a decimal number or
+ `*'.
+
+ In the first case, for integer and floating point
+ patterns, the object type is taken to be the
+ largest appropriate type (i.e., one of Sflong_t,
+ Sfulong_t or Sfdouble_t). For string patterns such
+ as %s, the flag is ignored.
+
+ In the second case, a given decimal value would
+ define a size while `*' would cause the size to be
+ obtained from the argument list. For string pat-
+ terns such as %s or %[, this size defines the
+ length of the buffer to store scanned data. Speci-
+ fying a buffer size only limits the amount of data
+ copied into the buffer. Scanned data beyond the
+ buffer limit will be discarded. For integer and
+ floating point patterns, the size is used to select
+ a type from one of the below lists as indicated by
+ the conversion specifier:
+
+ Sflong_t, long, int, short
+ Sfulong_t, unsigned long, unsigned int, unsigned short
+ Sfdouble_t, double, float
+
+ The selection algorithm always matches types from
+ left to right in any given list. Although selec-
+ tion is generally based on sizes in bytes, for com-
+ patibility with Microsoft-C, the size 64 is matched
+ with an appropriate type with the same number of
+ bits, if any. If the given size does not match any
+ of the listed types, it shall match one of int,
+ unsigned int, and double as indicated by the for-
+ matting pattern.
+
+ Below are examples of using the I flag. The first
+ example scans a 64-bit integer. The second scans
+ some floating point value whose size is explicitly
+ computed and given. The last example scans a
+ string into a buffer with the given size 128. Note
+
+
+
+ 05 August 1999 23
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ that if the scanned string is longer than 127, only
+ the first 127 bytes shall be copied into the
+ buffer. The rest of the scanned data shall be dis-
+ carded.
+
+ sfscanf(sfstdin,"%I64d", &int64_obj);
+ sfscanf(sfstdin,"%I*f", sizeof(float_obj), &float_obj);
+ sfscanf(sfstdin,"%I*s", 128, buffer);
+
+ Flags h, l, and L are the ANSI-C conventions for
+ indicating the type of a scanned element. For
+ example, %hd means scanning a short int. The flags
+ ll and L mean respectively scanning an integer or a
+ floating point value with largest size (i.e,
+ Sflong_t or Sfdouble_t).
+
+ The %i, %d and %u patterns scan numbers in bases from 2 to
+ 64. %i scans integral values in self-describing formats.
+ Except for octal, decimal and hexadecimal numbers with the
+ usual formats, numbers in general bases are assumed to be
+ of the form: _b_a_s_e_#_v_a_l_u_e where _b_a_s_e is a number in base 10
+ and _v_a_l_u_e is a number in the given base. For example,
+ 2#1001 is the binary representation of the decimal value
+ 9. If _b_a_s_e is 36 or less, the digits for _v_a_l_u_e can be any
+ combination of [0-9], [a-z], [A-Z] where upper and lower
+ case digits are not distinguishable. If _b_a_s_e is larger
+ than 36, the set of digits is:
+
+ 0123456789
+ abcdefghijklmnopqrstuvwxyz
+ ABCDEFGHIJKLMNOPQRSTUVWXYZ
+ @_
+
+
+
+ BBUUFFFFEERRIINNGG,, SSYYNNCCHHRROONNIIZZAATTIIOONN
+ VVooiidd__tt** ssffsseettbbuuff((SSffiioo__tt** ff,, VVooiidd__tt** bbuuff,, ssiizzee__tt ssiizzee))
+ This function sets the buffering scheme for the stream f.
+ Except for buffer inquiry (see the case size == 0,) f will
+ be synchronized before any buffer modification. If a new
+ buffer is successfully set and the old buffer has not been
+ deallocated, sfsetbuf() returns the address of the old
+ buffer. Otherwise, it returns NULL.
+
+ After a sfsetbuf() call, sfvalue() returns the size of the
+ returned buffer.
+
+ size == SF_UNBOUND:
+ Sfio will pick a suitable buffer size. If buf is
+ NULL, Sfio will also pick a suitable buffering
+ scheme (such as memory mapping.) If buf is not
+ NULL, its actual value is ignored but the buffer
+ will be allocated via malloc(3). This can be used
+ to avoid memory mapping.
+
+
+
+ 05 August 1999 24
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ size > 0:
+ This is the suggested size to use for buffering or
+ memory mapping. If buf is NULL, Sfio will pick a
+ suitable buffering scheme as discussed above. If
+ buf is not NULL, then buf and size determine a
+ buffer of the given size.
+
+ size == 0:
+ If buf is NULL, the stream will be unbuffered. If
+ buf is not NULL, sfsetbuf() simply returns the
+ stream buffer. In this case, no attempt will be
+ made to synchronize the stream.
+
+
+ iinntt ssffssyynncc((SSffiioo__tt** ff))
+ This function synchronizes the logical and physical views
+ of stream f. For a SF_WRITE stream, this means to write
+ out any buffered data. For a seekable SF_READ file
+ stream, the physical file position is aligned with the
+ logical stream position and, if SF_SHARE is on, buffered
+ data is discarded. If f is NULL, all streams are synchro-
+ nized. If f is the base of a stream stack (see sfs-
+ tack()), all stacked streams are synchronized. Note that
+ a stacked stream can only be synchronized this way. If f
+ is in a pool (see sfpool()) but not being the head, the
+ pool head is synchronized. After a successful synchro-
+ nization, if f has flag SF_IOCHECK, a SF_SYNC event is
+ raised. sfsync() returns a negative value for failure and
+ 0 for success.
+
+
+ iinntt ssffppoollll((SSffiioo__tt**** fflliisstt,, iinntt nn,, iinntt ttiimmeeoouutt))
+ This function polls a set of streams to see if I/O opera-
+ tions can be performed on them without blocking. This is
+ useful for multiplexing I/O over a set of streams. If a
+ stream has a discipline, the exception function may be
+ called before and after the stream is polled (see sfdisc()
+ for details). sfpoll() returns the number of ready
+ streams or -1 on failure.
+
+ flist and n:
+ flist is an array of n streams to be polled. Upon
+ return, ready streams are moved to the front of
+ flist in the same relative order.
+
+ timeout:
+ This defines an ellapse time in milliseconds to
+ wait to see if any stream is ready for I/O. If
+ timeout is negative, sfpoll() will block until some
+ stream become ready. Note that SF_STRING and nor-
+ mal file streams never block and are always ready
+ for I/O. If a stream with discipline is being
+ polled and its readiness is as yet undetermined
+ (e.g., empty buffer,) the discipline exception
+
+
+
+ 05 August 1999 25
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ function will be called with SF_DPOLL before normal
+ actions are taken.
+
+
+ SSffiioo__tt** ssffppooooll((SSffiioo__tt** ff,, SSffiioo__tt** ppoooollff,, iinntt mmooddee))
+ This function manipulates pools of streams. In a pool,
+ only one stream is at the head and can have buffered data.
+ All other streams in the pool will be synchronized. A
+ stream becomes head when it is used for some I/O opera-
+ tion. sfpool() returns NULL on failure.
+
+ f and poolf:
+ If f is NULL, sfpool() simply returns the head of
+ the pool containing poolf. If f is not NULL and
+ poolf is NULL, f is deleted from its pool. In this
+ case, if no other stream from the same pool can
+ become head, sfpool() will return NULL; otherwise,
+ it returns some stream from the remainder of the
+ pool. If both f and poolf are not NULL, f is moved
+ from its current pool (if any) into the same pool
+ with poolf. In this case, poolf is returned.
+
+ mode: If poolf is already in a pool, mode is ignored.
+ Otherwise, mode should be 0 or SF_SHARE. A
+ SF_SHARE pool contains streams with SF_WRITE mode.
+ In addition, on change to a new head stream,
+ buffered write data of the current head is trans-
+ ferred to the new head.
+
+
+ iinntt ssffppuurrggee((SSffiioo__tt** ff))
+ This function discards all buffered data unless f is a
+ SF_STRING stream. Note that if f is a SF_READ stream
+ based on an unseekable device, purged data will not be
+ recoverable. If f is a sfpopen-stream opened for both
+ read and write, data of both the read and write pipe ends
+ will be purged (see sfset() to selectively turn off read
+ or write mode if one set of data is to be preserved.)
+ After purging, if f has flag SF_IOCHECK, the event
+ SF_PURGE is raised. sfpurge() returns -1 for failure and
+ 0 for success.
+
+
+
+ DDIISSCCIIPPLLIINNEE,, EEVVEENNTT--HHAANNDDLLIINNGG
+ A file stream uses the system calls read(2), write(2) and
+ lseek(2) to read, write and position in the underlying
+ file. Disciplines enable application-defined I/O methods
+ including exception handling and data pre/post-processing.
+
+
+ SSffddiisscc__tt** ssffddiisscc((SSffiioo__tt** ff,, SSffddiisscc__tt** ddiisscc))
+ Each stream has a discipline stack whose bottom is a vir-
+ tual discipline representing the actual system calls.
+
+
+
+ 05 August 1999 26
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ sfdisc() manipulates the discipline stack of stream f. f
+ will be synchronized before any discipline stack manipula-
+ tion. After a successful discipline stack manipulation,
+ the stream I/O position (see sfseek() and sftell()) and
+ extent (see sfsize()) are updated to reflect that defined
+ by the top discipline. If disc is SF_POPDISC or
+ (Sfdisc_t*)0, the top element of the stack, if any, is
+ popped and its address is returned. Otherwise, disc is
+ pushed onto the discipline stack. In this case, if suc-
+ cessful, sfdisc() returns the discipline that was pushed
+ down. sfdisc() returns NULL on failure.
+
+ Note that a discipline can be used only on one stream at a
+ time. An application should take care to allocate differ-
+ ent discipline structures for use with different streams.
+ A discipline structure is of the type Sfdisc_t which con-
+ tains the following public fields:
+
+ Sfread_f readf;
+ Sfwrite_f writef;
+ Sfseek_f seekf;
+ Sfexcept_f exceptf;
+
+
+ The first three fields of Sfdisc_t specify alternative I/O
+ functions. If any of them is NULL, it is inherited from a
+ discipline pushed earlier on the stack. Note that a file
+ stream always has read(2), write(2), lseek(2) and
+ NIL(Sfexcept_f) as the _l_o_g_i_c_a_l _b_o_t_t_o_m _d_i_s_c_i_p_l_i_n_e. Argu-
+ ments to I/O discipline functions have the same meaning as
+ that of the functions sfrd(), sfwr() and sfsk() described
+ below.
+
+ The exception function, (*exceptf)() announces exceptional
+ events during I/O operations. It is called as
+ (*exceptf)(Sfio_t* f, int type, Void_t* value, Sfdisc_t*
+ disc). Unless noted otherwise, the return value of
+ (*exceptf)() is used as follows:
+
+ <0: The on-going operation shall terminate.
+
+ >0: If the event was raised due to an I/O error, the
+ error has been repaired and the on-going operation
+ shall continue normally.
+
+ =0: The on-going operation performs default actions
+ with respect to the raised event. For example, on
+ a reading error or reaching end of file, the top
+ stream of a stack will be popped and closed and the
+ on-going operation continue with the new top
+ stream.
+
+ The argument type of (*exceptf)() identifies the particu-
+ lar exceptional event:
+
+
+
+ 05 August 1999 27
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ SF_LOCKED:
+ The stream is in a locked state.
+
+ SF_READ, SF_WRITE:
+ These events are raised around reading and writing
+ operations.
+
+ If SF_IOCHECK is on, SF_READ and SF_WRITE are
+ raised immediately before read(2) and write(2)
+ calls. In this case, *((ssize_t*)value) is the
+ amount of data to be processed. The return value
+ of (*exceptf)(), if negative, indicates that the
+ stream is not ready for I/O and the calling opera-
+ tion will abort with failure. If it is positive,
+ the stream is ready for I/O but the amount should
+ be restricted to the amount specified by this
+ value. If the return value is zero, the I/O opera-
+ tion is carried out normally.
+
+ SF_READ and SF_WRITE are also raised on operation
+ failures. In such a case, *((ssize_t*)value) is
+ the return value from the failed operation.
+
+ SF_SEEK:
+ This event is raised when a seek operation fails.
+
+ SF_NEW, SF_CLOSE, SF_FINAL:
+ These events are raised during a stream closing.
+ SF_NEW is raised for a stream about to be closed to
+ be renewed (see sfnew()). SF_CLOSE is raised for a
+ stream about to be closed. SF_FINAL is raised
+ after a stream has been closed and before its space
+ is to be destroyed (see sfclose()). For these
+ events, a non-zero return value from (*exceptf)()
+ causes sfclose() to return immediately with the
+ same value.
+
+ SF_DPUSH, SF_DPOP, SF_DBUFFER:
+ Events SF_DPUSH and SF_DPOP are raised when a dis-
+ cipline is about to be pushed or popped.
+ (Sfdisc_t*)value is the to-be top discipline, if
+ any.
+
+ A stream buffer is always synchronized before push-
+ ing or popping a discipline. If this synchroniza-
+ tion fails, SF_DBUFFER will be raised with
+ *((size_t*)value) being the amount of buffered
+ data. If the return value of exceptf is positive,
+ the push or pop operation will continue normally;
+ otherwise, sfdisc() returns failure.
+
+ SF_DPOLL:
+ This event is raised by sfpoll() to see if the
+ stream is ready for I/O. *((int*)value) indicates
+
+
+
+ 05 August 1999 28
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ a time-out interval to wait. A negative return
+ value from the exception function means blocking.
+ A positive return value means non-blocking. A zero
+ return value means that sfpoll() should query the
+ stream file descriptor using default methods.
+
+ SF_READY:
+ This event is raised by sfpoll() for each ready
+ stream after they are determined. A negative
+ return value from the exeption handler causes
+ sfpoll() to return immediately with the same return
+ value. A positive return value causes sfpoll() to
+ retry polling the whole set of streams.
+
+ SF_SYNC, SF_PURGE:
+ If SF_IOCHECK is set, these events are raised imme-
+ diately after sfsync() or sfpurge() successfully
+ complete their operations and before they return.
+ Note that sfsync() is implied when a SF_WRITE or
+ SF_SHARE|SF_READ stream is closed. Note also that
+ SF_SYNC is not raised for a stream synchronized
+ during a call sfsync((Sfio_t*)0).
+
+ SF_ATEXIT:
+ This event is raised for each open stream before
+ the process exits.
+
+
+ iinntt ssffrraaiissee((SSffiioo__tt** ff,, iinntt ttyyppee,, VVooiidd__tt** ddaattaa))
+ This function calls all exception handlers of stream f
+ with the event type and associated data. If an exception
+ handler returns a non-zero value, sfraise() immediate
+ returns the same value. Application-defined events should
+ start from the value SF_EVENT so as to avoid confusion
+ with system-defined events, sfraise() returns 0 on success
+ and -1 on failure.
+
+
+ ssssiizzee__tt ssffrrdd((SSffiioo__tt** ff,, VVooiidd__tt** bbuuff,, ssiizzee__tt nn,, SSffddiisscc__tt**
+ ddiisscc))
+ ssssiizzee__tt ssffwwrr((SSffiioo__tt** ff,, ccoonnsstt VVooiidd__tt** bbuuff,, ssiizzee__tt nn,,
+ SSffddiisscc__tt** ddiisscc))
+ SSffooffff__tt ssffsskk((SSffiioo__tt** ff,, SSffooffff__tt ooffffsseett,, iinntt ttyyppee,, SSffddiisscc__tt**
+ ddiisscc))
+ These functions provides safe methods for a discipline I/O
+ function to invoke earlier discipline I/O functions and to
+ properly handle exceptions. They should not be used in
+ any other context. sfrd() and sfwr() return the number of
+ bytes read or written. sfsk() returns the new seek posi-
+ tion. On error, all three functions return a negative
+ value which should be -1 or the value returned by the
+ exception handler.
+
+
+
+
+
+ 05 August 1999 29
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ SSTTRREEAAMM CCOONNTTRROOLL
+ iinntt ssffsseett((SSffiioo__tt** ff,, iinntt ffllaaggss,, iinntt sseett))
+ This function sets control flags for the stream f. It
+ returns the previous set of flags or 0 on error.
+
+ Settable flags are: SF_READ, SF_WRITE, SF_IOCHECK,
+ SF_LINE, SF_SHARE, SF_PUBLIC, SF_MALLOC, SF_STATIC and
+ SF_BUFCONST. Note that SF_READ and SF_WRITE can be turned
+ on or off only if the stream was opened as
+ SF_READ|SF_WRITE. Turning off one of them means that the
+ stream is to be treated exclusively in the other mode. It
+ is not possible to turn off both. If legal, an attempt to
+ turn on either SF_READ or SF_WRITE will cause the stream
+ to be in the given I/O mode.
+
+ set == 0:
+ If flags is zero, the current set of flags is sim-
+ ply returned. Note that when a stream is first
+ opened, not all of its flags are initialized yet
+ (more below). If flags is non-zero, an attempt is
+ made to turn off the specified flags.
+
+ set != 0:
+ If flags is zero, the stream is initialized if not
+ yet done so. Then the current set of flags is
+ returned. If flags is non-zero, an attempt is made
+ to turn on the specified flags.
+
+
+ iinntt ssffsseettffdd((SSffiioo__tt** ff,, iinntt ffdd))
+ This function changes the file descriptor of f. Before a
+ change is realized, (*notify)(f,SF_SETFD,newfd) (see sfno-
+ tify()) is called. sfsetfd() returns -1 on failure and
+ the new file descriptor on success.
+
+ fd >= 0:
+ If the current file descriptor is non-negative, it
+ will be changed using dup(3) to a value larger or
+ equal to fd. Upon a successful change, the previ-
+ ous file descriptor will be closed. If the current
+ file descriptor is negative, it will be set to fd
+ and the stream will be reinitialized.
+
+ fd < 0:
+ The stream is synchronized (see sfsync()) and its
+ file descriptor will be set to this value. Then,
+ except for sfclose(), the stream will be inaccessi-
+ ble until a future sfsetfd() call resets the file
+ descriptor to a non-negative value. Thus,
+ sfsetfd(f,-1) can be used to avoid closing the file
+ descriptor of f when f is closed.
+
+
+
+
+
+
+ 05 August 1999 30
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ SSffiioo__tt** ssffssttaacckk((SSffiioo__tt** bbaassee,, SSffiioo__tt** ttoopp))
+ This function stacks or unstacks stream. Every stream
+ stack is identified by a base stream via which all I/O
+ operations are performed. However, an I/O operation
+ always takes effect on the top stream. If the top stream
+ reaches the end of file or has an unrecoverable error con-
+ dition, it is automatically popped and closed (see also
+ sfdisc() for alternative handling of these conditions).
+
+ base: This is the base stream of the stack. If it is
+ NULL, sfstack() does nothing and returns top.
+
+ top: If this is SF_POPSTACK or (Sfio_t*)0, the stack is
+ popped and sfstack() returns the popped stream.
+ Otherwise, top is pushed on top of the stack iden-
+ tified by base and sfstack() returns the base
+ stream.
+
+
+ SSffiioo__tt** ssffsswwaapp((SSffiioo__tt** ff11,, SSffiioo__tt** ff22))
+ This function swaps contents of f1 and f2. This fails if
+ either stream is in a stream stack but not being a base
+ stream. If f2 is NULL, a new stream is constructed as a
+ duplicate of f1. sfswap() returns f2 or f1 duplicate on
+ success and NULL on failure.
+
+
+
+ SSTTRREEAAMM IINNFFOORRMMAATTIIOONN
+ SSffooffff__tt ssffssiizzee((SSffiioo__tt** ff))
+ This function returns the size of stream f (see sfnew()).
+ If f is not seekable or if its size is not determinable,
+ sfsize() returns -1.
+
+
+ SSffooffff__tt ssfftteellll((SSffiioo__tt** ff))
+ This function returns the current I/O position in stream
+ f. Note that if f is SF_APPEND and a writing operation
+ was just performed, the current I/O position is at the
+ physical end of file. If f is unseekable, sftell returns
+ the number of bytes read from or written to f. See also
+ sfungetc().
+
+
+ ssssiizzee__tt ssffvvaalluuee((SSffiioo__tt** ff))
+ This function returns the string or buffer length for
+ sfreserve(), sfsetbuf(), and sfgetr().
+
+
+ iinntt ssffffiilleennoo((SSffiioo__tt** ff))
+ This function returns the file descriptor of stream f.
+
+
+
+
+
+
+ 05 August 1999 31
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ iinntt ssffssttaacckkeedd((SSffiioo__tt** ff))
+ This function returns a non-zero value if stream f has
+ been stacked.
+
+
+ iinntt ssffeeooff((SSffiioo__tt** ff))
+ iinntt ssffeerrrroorr((SSffiioo__tt** ff))
+ iinntt ssffccllrreerrrr((SSffiioo__tt** ff))
+ sfeof() tells whether or not the stream has an end-of-file
+ condition. sferror() tells whether or not the stream has
+ an error condition. sfclrerr() clears both end-of-file
+ and error conditions. The end-of-file and error condi-
+ tions are also cleared on an I/O operation.
+
+
+ iinntt ssffccllrrlloocckk((SSffiioo__tt** ff))
+ This function restores the stream back to a normal state.
+ This means clearing locks and possibly throwing away
+ unprocessed data. As such, this operation is unsafe and
+ should be used with care. For example, it may be used
+ before a long jump (longjmp(3)) out of some discipline I/O
+ function to restore the internal stream states. sfclr-
+ lock() returns the current set of flags.
+
+
+ iinntt ssffnnoottiiffyy((((vvooiidd((**))nnoottiiffyy))((SSffiioo__tt**,, iinntt,, iinntt)) ))
+ This sets a function (*notify)() to be called as
+ (*notify)(f,type,file) on various stream events. Argu-
+ ments f and file are stream and related file descriptor.
+ Argument type indicates the reason for the call:
+
+ SF_NEW:
+ f is being opened and file is the underlying file
+ descriptor.
+
+ SF_CLOSE:
+ f and file are being closed.
+
+ SF_SETFD:
+ The file descriptor of f is being changed to file
+ (see sfsetfd().)
+
+ SF_READ:
+ An attempt to change f to read mode failed.
+
+ SF_WRITE:
+ An attempt to change f to write mode failed.
+
+
+
+ MMIISSCCEELLLLAANNEEOOUUSS FFUUNNCCTTIIOONNSS
+ ssssiizzee__tt ssffsslleenn(())
+ This function returns the length of a string just con-
+ structed by sfsprintf() or sfprints(). See also
+
+
+
+ 05 August 1999 32
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ sfvalue().
+
+
+ iinntt ssffuulleenn((SSffuulloonngg__tt vv))
+ iinntt ssfflllleenn((SSfflloonngg__tt vv))
+ iinntt ssffddlleenn((SSffddoouubbllee__tt vv))
+ These functions return respectively the number of bytes
+ required to code the Sfulong_t, Sflong_t or Sfdouble_t
+ value v by sfputu(), sfputl() or sfputd().
+
+
+ ssssiizzee__tt ssffppkkrrdd((iinntt ffdd,, cchhaarr** bbuuff,, ssiizzee__tt nn,, iinntt rrsscc,, lloonngg
+ ttmm,, iinntt aaccttiioonn))
+ This function acts directly on the file descriptor fd. It
+ does a combination of peeking on incoming data and a time-
+ out read. Upon success, it returns the number of bytes
+ received. A return value of 0 means that the end-of-file
+ condition has been detected. A negative value represents
+ an error.
+
+ buf, n:
+ These define a buffer and its size to read data
+ into.
+
+ rsc: If >=0, this defines a record separator. See
+ action for detail.
+
+ tm: If >=0, this defines a time interval in millisec-
+ onds to wait for incoming data.
+
+ action:
+ When rsc >= 0, the absolute value of action, _r,
+ determines the number of records to be read. If
+ action > 0, sfpkrd() will peek on incoming data but
+ will not read past it. Therefore, a future sfpkrd()
+ or read(2) will see the same data again. If action
+ == 0, sfpkrd() will not peek. If action < 0, there
+ are two cases: if rsc < 0, sfpkrd() reads n bytes;
+ otherwise, exactly _r records will be read. Note
+ that, in the last case, reading records from an
+ unseekable device may be slow if the underlying
+ platform does not allow peeking on such a device.
+
+
+
+ FFUULLLL SSTTRRUUCCTTUURREE SSFFIIOO__TT
+ ##iinncclluuddee <<ssffiioo__tt..hh>>
+ Most applications based on Sfio only need to include the
+ header file sfio.h which defines an abbreviated Sfio_t
+ structure without certain fields private to Sfio. How-
+ ever, there are times (e.g., debugging) when an applica-
+ tion may require more details about the full Sfio_t struc-
+ ture. In such cases, the header file sfio_t.h can be used
+ in place of sfio.h. Note that an application doing this
+
+
+
+ 05 August 1999 33
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ will become sensitive to changes in the internal architec-
+ ture of Sfio.
+
+
+ ##ddeeffiinnee SSFFNNEEWW((bbuuff,,ssiizzee,,ffiillee,,ffllaaggss,,ddiisscc))
+ This macro function is defined in sfio_t.h for use in
+ static initialization of an Sfio_t structure. It requires
+ five arguments:
+
+ buf, size:
+ These define a buffer and its size.
+
+ file: This defines the underlying file descriptor if any.
+
+ flags: This is composed from bit flags described above.
+
+ disc: This defines a discipline if any.
+
+
+
+ EEXXAAMMPPLLEE DDIISSCCIIPPLLIINNEESS
+ The below functions create disciplines and insert them
+ into the given streams f. These functions return 0 on suc-
+ cess and -1 on failure.
+
+
+ iinntt ssffddccddiioo((SSffiioo__tt** ff,, ssiizzee__tt bbuuffssiizzee))
+ This creates a discipline that uses the direct IO feature
+ available on file systems such as SGI's XFS to speed up
+ IO. The argument bufsize suggests a buffer size to use
+ for data transfer.
+
+
+ iinntt ssffddccddooss((SSffiioo__tt** ff))
+ This creates a discipline to read DOS text files. It
+ basically transforms pairs of \r\n to \n.
+
+
+ iinntt ssffddccffiilltteerr((SSffiioo__tt** ff,, ccoonnsstt cchhaarr** ccmmdd))
+ This creates a discipline that sends data from f to the
+ given command cmd to process, then reads back the pro-
+ cessed data.
+
+
+ iinntt ssffddccllzzww((SSffiioo__tt** ff))
+ This creates a discipline that would decompress data in f.
+ The stream f should have data from a source compressed by
+ the Unix ccoommpprreessss program.
+
+
+ iinntt ssffddccsseeeekkaabbllee((SSffiioo__tt** ff))
+ This creates a discipline that makes an unseekable reading
+ stream seekable.
+
+
+
+
+ 05 August 1999 34
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ iinntt ssffddccssllooww((SSffiioo__tt** ff))
+ This creates a discipline that makes all Sfio operations
+ return immediately on interrupts. This is useful for deal-
+ ing with slow devices.
+
+
+ iinntt ssffddccssuubbssttrreeaamm((SSffiioo__tt** ff,, SSffiioo__tt** ppaarreenntt,, SSffooffff__tt ooffffsseett,,
+ SSffooffff__tt eexxtteenntt))
+ This creates a discipline that makes f acts as if it cor-
+ responds exactly to the subsection of parent starting at
+ offset with size extent.
+
+
+ iinntt ssffddcctteeee((SSffiioo__tt** ff,, SSffiioo__tt** tteeee))
+ This creates a discipline that copies to the stream tee
+ any data written to f.
+
+
+ iinntt ssffddccuunniioonn((SSffiioo__tt** ff,, SSffiioo__tt**** aarrrraayy,, iinntt nn))
+ This creates a discipline that makes f act as if it is the
+ concatenation of the n streams given in array.
+
+
+
+ SSTTDDIIOO--CCOOMMPPAATTIIBBIILLIITTYY
+ Sfio provides two compatibility packages to Stdio-based
+ applications, a source level interface and a binary level
+ library. These packages provide a union of functions in
+ popular Stdio implementations.
+
+ The source Stdio-compatibility interface provides the
+ header file stdio.h that defines a set of macros or
+ inlined functions to map Stdio calls to Sfio ones. This
+ mapping may benignly extend or change the meaning of cer-
+ tain original Stdio operations. For example, the Sfio's
+ version of popen() allows a coprocess to be opened for
+ both reading and writing unlike the original call which
+ only allows a coprocess to be opened for a single mode.
+ Similarly, the Sfio's fopen() call can be used to create
+ string streams in addition to file streams.
+
+ The binary Stdio-compatibility library, libstdio.a, pro-
+ vides a complete implementation of Stdio functions suit-
+ able for linking applications already compiled with native
+ header stdio.h. Functions in this implementation are also
+ slightly altered or extended as discussed above.
+
+ Below are the supported Stdio functions:
+
+ FILE* fopen(const char* file, const char* mode);
+ FILE* freopen(const char* file, const char* mode, FILE* stream);
+ FILE* fdopen(int filedesc, const char* mode);
+ FILE* popen(const char* command, const char* mode);
+ FILE* tmpfile();
+
+
+
+ 05 August 1999 35
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ int fclose(FILE* stream);
+ int pclose(FILE* stream);
+
+ void setbuf(FILE* stream, char* buf);
+ int setvbuf(FILE* stream, char* buf, int mode, size_t size);
+ void setbuffer(FILE* stream, char* buf, size_t size);
+ int setlinebuf(FILE* stream);
+ int fflush(FILE* stream);
+ int fpurge(FILE* stream);
+
+ int fseek(FILE* stream, long offset, int whence);
+ void rewind(FILE* stream);
+ int fgetpos(FILE* stream, fpos_t* pos);
+ int fsetpos(FILE* stream, fpos_t* pos);
+ long ftell(FILE* stream);
+
+ int getc(FILE* stream);
+ int fgetc(FILE* stream);
+ int getchar(void);
+ int ungetc(int c, FILE* stream);
+ int getw(FILE* stream);
+ char* gets(char* s);
+ char* fgets(char* s, int n, FILE* stream);
+ size_t fread(Void_t* ptr, size_t size, size_t nelt, FILE* stream);
+
+ int putc(int c, FILE* stream);
+ int fputc(int c, FILE* stream);
+ int putchar(int c);
+ int putw(int w, FILE* stream);
+ int puts(const char* s, FILE* stream);
+ int fputs(const char* s, FILE* stream);
+ size_t fwrite(const Void_t* ptr, size_t size, size_t nelt, FILE* stream);
+
+ int fscanf(FILE* stream, const char* format, ...);
+ int vfscanf(FILE* stream, const char* format, va_list args);
+ int _doscan(FILE* stream, const char* format, va_list args);
+ int scanf(const char* format, ...);
+ int vscanf(const char* format, va_list args);
+ int sscanf(const char* s, const char* format, ...);
+ int vsscanf(const char* s, const char* format, va_list args);
+
+ int fprintf(FILE* stream, const char* format, ...);
+ int vfprintf(FILE* stream, const char* format, va_list args);
+ int _doprnt(FILE* stream, const char* format, va_list args);
+ int printf(const char* format, ...);
+ int vprintf(const char* format, va_list args);
+ int sprintf(const char* s, const char* format, ...);
+ int snprintf(const char* s, int n, const char* format, ...);
+ int vsprintf(const char* s, const char* format, va_list args);
+ int vsnprintf(const char* s, int n, const char* format, va_list args);
+
+ int feof(FILE* stream);
+ int ferror(FILE* stream);
+ int clearerr(FILE* stream);
+
+
+
+ 05 August 1999 36
+
+
+
+
+
+ SFIO(3) SFIO(3)
+
+
+ RREECCEENNTT CCHHAANNGGEESS
+ A few exception types have been added. In particular,
+ exception handlers shall be raised with SF_LOCKED on
+ accessing a locked stream. Before a process exits, the
+ event SF_ATEXIT is raised for each open stream.
+
+ A number of disciplines have been added for various pro-
+ cessing functions. Of interests are disciplines to use
+ the direct I/O feature on IRIX6.2, read DOS text files,
+ and decompress files compressed by Unix _c_o_m_p_r_e_s_s.
+
+ Various new stream and function flags have been added. For
+ example, the third argument of sfgetr() is now a set of
+ bit flags and not just a three-value object. However, the
+ old semantics of this argument of sfgetr() is still sup-
+ ported.
+
+ The sfopen() call has been extended so that
+ sfopen(f,NULL,mode) can be used to changed the mode of a
+ file stream before any I/O operations. This is most use-
+ ful for changing the modes of the standard streams.
+
+ The buffering strategy has been significantly enhanced for
+ streams that perform many seek operations. Also, the han-
+ dling of stream and file positions have been better clari-
+ fied so that applications that share file descriptors
+ across streams and/or processes can be sure that the file
+ states will be consistent.
+
+
+ AAUUTTHHOORRSS
+ Kiem-Phong Vo, kpv@research.att.com,
+ David G. Korn, dgk@research.att.com, and
+ Glenn S. Fowler, gsf@research.att.com.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ 05 August 1999 37
+
+
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