NAME

       BIO_find_type, BIO_next, BIO_method_type - BIO chain traversal

SYNOPSIS

        #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);

DESCRIPTION

       The BIO_find_type() searches for a BIO of a given type in a chain, starting at BIO b. If
       type is a specific type (such as BIO_TYPE_MEM) then a search is made for a BIO of that
       type. If type is a general type (such as BIO_TYPE_SOURCE_SINK) then the next matching BIO
       of the given general type is searched for. BIO_find_type() returns the next matching BIO
       or NULL if none is found.

       The following general types are defined: BIO_TYPE_DESCRIPTOR, BIO_TYPE_FILTER, and
       BIO_TYPE_SOURCE_SINK.

       For a list of the specific types, see the openssl/bio.h header file.

       BIO_next() returns the next BIO in a chain. It can be used to traverse all BIOs in a chain
       or used in conjunction with BIO_find_type() to find all BIOs of a certain type.

       BIO_method_type() returns the type of a BIO.

RETURN VALUES

       BIO_find_type() returns a matching BIO or NULL for no match.

       BIO_next() returns the next BIO in a chain.

       BIO_method_type() returns the type of the BIO b.

EXAMPLE

       Traverse a chain looking for digest BIOs:

        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);

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 <https://www.openssl.org/source/license.html>.