NAME

BIO_find_type, BIO_next − 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_NONE0
#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_DESCRIPTOR0x0100
#define BIO_TYPE_FILTER0x0200
#define BIO_TYPE_SOURCE_SINK0x0400

DESCRIPTION

The BIO_find_type() function 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 sought. The BIO_find_type()function returns the next matching BIO or NULL if none is found. 

Note

Some BIO_TYPE_∗ types do not have corresponding BIO implementations. 

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

The BIO_method_type() function returns the type of a BIO. 

NOTES

The BIO_next() function was added to OpenSSL 0.9.6 to provide a clean way to traverse a BIO chain or find multiple matches using the BIO_find_type() function. Previous versions used the following:

 next = bio->next_bio;

RESTRICTIONS

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

RETURN VALUES

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

The BIO_next() function returns the next BIO in a chain. 

The BIO_method_type() function 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);

SEE ALSO

TBA