SSL_get_rbio

 #include <openssl/ssl.h>
 BIO *SSL_get_rbio(SSL *ssl);
 BIO *SSL_get_wbio(SSL *ssl);

SSL_get_rbio() and SSL_get_wbio() return pointers to the BIOs for the read or the write channel, which can be different. The reference count of the BIO is not incremented.

The following return values can occur:

NULL

No BIO was connected to the SSL object

Any other pointer

The BIO linked to ssl.

SSL_set_bio(3), ssl(3) , bio(3)