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✏️ Editing: BIO_next.3

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.\" ========================================================================
.\"
.IX Title "BIO_FIND_TYPE 3"
.TH BIO_FIND_TYPE 3 "2023-09-11" "1.1.1w" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.nh
.SH "NAME"
BIO_find_type, BIO_next, BIO_method_type \- BIO chain traversal
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/bio.h>
\&
\& BIO *BIO_find_type(BIO *b, int bio_type);
\& BIO *BIO_next(BIO *b);
\& int BIO_method_type(const BIO *b);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The \fBBIO_find_type()\fR searches for a \s-1BIO\s0 of a given type in a chain, starting
at \s-1BIO\s0 \fBb\fR. If \fBtype\fR is a specific type (such as \fB\s-1BIO_TYPE_MEM\s0\fR) then a search
is made for a \s-1BIO\s0 of that type. If \fBtype\fR is a general type (such as
\&\fB\s-1BIO_TYPE_SOURCE_SINK\s0\fR) then the next matching \s-1BIO\s0 of the given general type is
searched for. \fBBIO_find_type()\fR returns the next matching \s-1BIO\s0 or \s-1NULL\s0 if none is
found.
.PP
The following general types are defined:
\&\fB\s-1BIO_TYPE_DESCRIPTOR\s0\fR, \fB\s-1BIO_TYPE_FILTER\s0\fR, and \fB\s-1BIO_TYPE_SOURCE_SINK\s0\fR.
.PP
For a list of the specific types, see the \fBopenssl/bio.h\fR header file.
.PP
\&\fBBIO_next()\fR returns the next \s-1BIO\s0 in a chain. It can be used to traverse all BIOs
in a chain or used in conjunction with \fBBIO_find_type()\fR to find all BIOs of a
certain type.
.PP
\&\fBBIO_method_type()\fR returns the type of a \s-1BIO.\s0
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fBBIO_find_type()\fR returns a matching \s-1BIO\s0 or \s-1NULL\s0 for no match.
.PP
\&\fBBIO_next()\fR returns the next \s-1BIO\s0 in a chain.
.PP
\&\fBBIO_method_type()\fR returns the type of the \s-1BIO\s0 \fBb\fR.
.SH "EXAMPLES"
.IX Header "EXAMPLES"
Traverse a chain looking for digest BIOs:
.PP
.Vb 1
\& BIO *btmp;
\&
\& btmp = in_bio; /* in_bio is chain to search through */
\& do {
\&     btmp = BIO_find_type(btmp, BIO_TYPE_MD);
\&     if (btmp == NULL)
\&         break; /* Not found */
\&     /* btmp is a digest BIO, do something with it ...*/
\&     ...
\&
\&     btmp = BIO_next(btmp);
\& } while (btmp);
.Ve
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2000\-2019 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the OpenSSL license (the \*(L"License\*(R").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file \s-1LICENSE\s0 in the source distribution or at
<https://www.openssl.org/source/license.html>.

MR SKB