/usr/man/cat.3/BIO_find_type.3

BIO_find_type(3)             OpenSSL             BIO_find_type(3)

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);

      #define BIO_method_type(b)             ((b)->method->type)

      #define BIO_TYPE_NONE          0
      #define BIO_TYPE_MEM           (1|0x0400)
      #define BIO_TYPE_FILE          (2|0x0400)

      #define BIO_TYPE_FD            (4|0x0400|0x0100)
      #define BIO_TYPE_SOCKET                (5|0x0400|0x0100)
      #define BIO_TYPE_NULL          (6|0x0400)
      #define BIO_TYPE_SSL           (7|0x0200)
      #define BIO_TYPE_MD            (8|0x0200)
      #define BIO_TYPE_BUFFER                (9|0x0200)
      #define BIO_TYPE_CIPHER                (10|0x0200)
      #define BIO_TYPE_BASE64                (11|0x0200)
      #define BIO_TYPE_CONNECT       (12|0x0400|0x0100)
      #define BIO_TYPE_ACCEPT                (13|0x0400|0x0100)
      #define BIO_TYPE_PROXY_CLIENT  (14|0x0200)
      #define BIO_TYPE_PROXY_SERVER  (15|0x0200)
      #define BIO_TYPE_NBIO_TEST     (16|0x0200)
      #define BIO_TYPE_NULL_FILTER   (17|0x0200)
      #define BIO_TYPE_BER           (18|0x0200)
      #define BIO_TYPE_BIO           (19|0x0400)

      #define BIO_TYPE_DESCRIPTOR    0x0100
      #define BIO_TYPE_FILTER                0x0200
      #define BIO_TYPE_SOURCE_SINK   0x0400

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.

     Note: not all the BIO_TYPE_* types above have corresponding
     BIO implementations.

     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.

1.0.2t               Last change: 2019-09-10                    1

BIO_find_type(3)             OpenSSL             BIO_find_type(3)

     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.

NOTES

     BIO_next() was added to OpenSSL 0.9.6 to provide a 'clean'
     way to traverse a BIO chain or find multiple matches using
     BIO_find_type(). Previous versions had to use:

      next = bio->next_bio;

BUGS

     BIO_find_type() in OpenSSL 0.9.5a and earlier could not be
     safely passed a NULL pointer for the b argument.

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);

SEE ALSO

     TBA

1.0.2t               Last change: 2019-09-10                    2

See also BIO_method_type(3)
See also BIO_next(3)