BIO_find_type, BIO_next, BIO_method_type - BIO chain traversal

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       Licensed under the Apache License 2.0 (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>.

3.5.0                                              2025-06-04                                BIO_FIND_TYPE(3SSL)

       The BIO_find_type() searches for a BIO of a given type in a chain, starting at BIOb. 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. If type is BIO_TYPE_NONE it will
       not find a match.

       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.

       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);

       BIO_find_type, BIO_next, BIO_method_type - BIO chain traversal

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.

        #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);