##
##  val - OSSP Value Library
##  Copyright (c) 2002 Ralf S. Engelschall <rse@engelschall.com>
##  Copyright (c) 2002 The OSSP Project <http://www.ossp.org/>
##  Copyright (c) 2002 Cable & Wireless Deutschland <http://www.cw.com/de/>
##
##  This file is part of OSSP val, a Value library which
##  can be found at http://www.ossp.org/pkg/val/.
##
##  Permission to use, copy, modify, and distribute this software for
##  any purpose with or without fee is hereby granted, provided that
##  the above copyright notice and this permission notice appear in all
##  copies.
##
##  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
##  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
##  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
##  IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
##  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
##  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
##  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
##  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
##  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
##  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
##  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
##  SUCH DAMAGE.
##
##  val.pod: library manual page
##

=pod

=head1 NAME

B<OSSP val> - Value Library

=head1 SYNOPSIS

=over 4

=item B<Constants>

C<VAL_MAXNAME>, 
C<VAL_TYPE_VAL>,
C<VAL_TYPE_PTR>,
C<VAL_TYPE_CHAR>,
C<VAL_TYPE_SHORT>,
C<VAL_TYPE_INT>,
C<VAL_TYPE_LONG>,
C<VAL_TYPE_FLOAT>,
C<VAL_TYPE_DOUBLE>
C<VAL_OK>,
C<VAL_ERR_ARG>,
C<VAL_ERR_USE>,
C<VAL_ERR_MEM>,
C<VAL_ERR_HSH>,
C<VAL_ERR_INT>,
C<VAL_ERR_SYS>.

=item B<Data Types>

C<val_t>,
C<val_cb_t>,
C<val_rc_t>.

=item B<Functions>

C<val_create>,
C<val_destroy>,
C<val_reg>,
C<val_query>,
C<val_set>,
C<val_get>,
C<val_vset>,
C<val_vget>,
C<val_apply>.

=back

=head1 DESCRIPTION

B<OSSP val> is a flexible name to value mapping library for C variables.
It allows one to access C variables through name strings, although
the C language does neither provide such a dedicated facility nor an
evaluation construct (which could be used to implement such a facility
easily). In general, it is interesting whenevery you need access to C
variable symbols without having to know the actual address/reference.
The typical use cases are in combination with flexible configuration
parsing and supporting loosly-coupled DSO-based module architectures.

=head1 API CONSTANTS

=over 4

=item C<VAL_MAXNAME>

=item C<VAL_TYPE_>I<ID>

C<VAL_TYPE_VAL>,
C<VAL_TYPE_PTR>,
C<VAL_TYPE_CHAR>,
C<VAL_TYPE_SHORT>,
C<VAL_TYPE_INT>,
C<VAL_TYPE_LONG>,
C<VAL_TYPE_FLOAT>,
C<VAL_TYPE_DOUBLE>

=item C<VAL_OK>, C<VAL_ERR_>I<ID>

C<VAL_ERR_ARG>,
C<VAL_ERR_USE>,
C<VAL_ERR_MEM>,
C<VAL_ERR_HSH>,
C<VAL_ERR_INT>,
C<VAL_ERR_SYS>.

=back

=head1 API DATA TYPES

=over 4

=item C<val_t>

=item C<val_cb_t>

=item C<val_rc_t>

=back

=head1 API FUNCTIONS

=over 4

=item val_rc_t B<val_create>(val_t **I<pval>);

=item val_rc_t B<val_destroy>(val_t *I<val>);

=item val_rc_t B<val_reg>(val_t *I<val>, const char *I<name>, int I<type>, const char *I<desc>, void *I<storage>);

=item val_rc_t B<val_query>(val_t *I<val>, const char *I<name>, int *I<ptype>, char **I<pdesc>, void **I<pstorage>);

=item val_rc_t B<val_set>(val_t *I<val>, const char *I<name>, ...);

=item val_rc_t B<val_get>(val_t *I<val>, const char *I<name>, ...);

=item val_rc_t B<val_vset>(val_t *I<val>, const char *I<name>, va_list I<ap>);

=item val_rc_t B<val_vget>(val_t *I<val>, const char *I<name>, va_list I<ap>);

=item val_rc_t B<val_apply>(val_t *I<val>, const char *I<name>, int I<depth>, val_cb_t I<cb>, void *I<ctx>);

=back

=head1 SEE ALSO

OSSP var.

=head1 HISTORY

B<OSSP val> was invented in January 2002 by Thomas Lotterer and Ralf S.
Engelschall for use inside the OSSP lmtp2nntp project.

=head1 AUTHORS

 Thomas Lotterer
 Ralf S. Engelschall

=cut