+++ /dev/null
-=pod
-
-=head1 NAME
-
-BIO_set_callback, BIO_get_callback, BIO_set_callback_arg, BIO_get_callback_arg,
-BIO_debug_callback - BIO callback functions
-
-=head1 SYNOPSIS
-
- #include <openssl/bio.h>
-
-
- typedef long (*BIO_callback_fn)(BIO *b, int oper, const char *argp, int argi,
- long argl, long ret);
-
- void BIO_set_callback(BIO *b, BIO_callack_fn cb);
- BIO_callack_fn BIO_get_callback(BIO *b);
- void BIO_set_callback_arg(BIO *b, char *arg);
- char *BIO_get_callback_arg(const BIO *b);
-
- long BIO_debug_callback(BIO *bio, int cmd, const char *argp, int argi,
- long argl, long ret);
-
-=head1 DESCRIPTION
-
-BIO_set_callback() and BIO_get_callback() set and retrieve the BIO callback,
-they are both macros. The callback is called during most high level BIO
-operations. It can be used for debugging purposes to trace operations on
-a BIO or to modify its operation.
-
-BIO_set_callback_arg() and BIO_get_callback_arg() are macros which can be
-used to set and retrieve an argument for use in the callback.
-
-BIO_debug_callback() is a standard debugging callback which prints
-out information relating to each BIO operation. If the callback
-argument is set it is interpreted as a BIO to send the information
-to, otherwise stderr is used.
-
-BIO_callback_fn() is the type of the callback function. The meaning of each
-argument is described below:
-
-=over
-
-=item B<b>
-
-The BIO the callback is attached to is passed in B<b>.
-
-=item B<oper>
-
-B<oper> is set to the operation being performed. For some operations
-the callback is called twice, once before and once after the actual
-operation, the latter case has B<oper> or'ed with BIO_CB_RETURN.
-
-=item B<argp> B<argi> B<argl>
-
-The meaning of the arguments B<argp>, B<argi> and B<argl> depends on
-the value of B<oper>, that is the operation being performed.
-
-=item B<ret>
-
-B<ret> is the return value that would be returned to the
-application if no callback were present. The actual value returned
-is the return value of the callback itself. In the case of callbacks
-called before the actual BIO operation 1 is placed in B<ret>, if
-the return value is not positive it will be immediately returned to
-the application and the BIO operation will not be performed.
-
-=back
-
-The callback should normally simply return B<ret> when it has
-finished processing, unless it specifically wishes to modify the
-value returned to the application.
-
-=head1 CALLBACK OPERATIONS
-
-In the notes below, B<callback> defers to the actual callback
-function that is called.
-
-=over 4
-
-=item B<BIO_free(b)>
-
-callback(b, BIO_CB_FREE, NULL, 0L, 0L, 1L) is called before the
-free operation.
-
-=item B<BIO_read(b, out, outl)>
-
-callback(b, BIO_CB_READ, out, outl, 0L, 1L) is called before
-the read and callback(b, BIO_CB_READ|BIO_CB_RETURN, out, outl, 0L, retvalue)
-after.
-
-=item B<BIO_write(b, in, inl)>
-
-callback(b, BIO_CB_WRITE, in, inl, 0L, 1L) is called before
-the write and callback(b, BIO_CB_WRITE|BIO_CB_RETURN, in, inl, 0L, retvalue)
-after.
-
-=item B<BIO_gets(b, out, outl)>
-
-callback(b, BIO_CB_GETS, out, outl, 0L, 1L) is called before
-the operation and callback(b, BIO_CB_GETS|BIO_CB_RETURN, out, outl, 0L, retvalue)
-after.
-
-=item B<BIO_puts(b, in)>
-
-callback(b, BIO_CB_WRITE, in, 0, 0L, 1L) is called before
-the operation and callback(b, BIO_CB_WRITE|BIO_CB_RETURN, in, 0, 0L, retvalue)
-after.
-
-=item B<BIO_ctrl(BIO *b, int cmd, long larg, void *parg)>
-
-callback(b, BIO_CB_CTRL, parg, cmd, larg, 1L) is called before the call and
-callback(b, BIO_CB_CTRL|BIO_CB_RETURN, parg, cmd, larg, ret) after.
-
-=back
-
-=head1 EXAMPLE
-
-The BIO_debug_callback() function is a good example, its source is
-in crypto/bio/bio_cb.c
-
-=head1 COPYRIGHT
-
-Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
-
-Licensed under the OpenSSL license (the "License"). You may not use
-this file except in compliance with the License. You can obtain a copy
-in the file LICENSE in the source distribution or at
-L<https://www.openssl.org/source/license.html>.
-
-=cut
projects / openssl.git / blobdiff