SSL_get_fd - get file descriptor linked to an SSL object
int SSL_get_fd(SSL *ssl); int SSL_get_rfd(SSL *ssl); int SSL_get_wfd(SSL *ssl);
SSL_get_fd() returns the file descriptor which is linked to ssl.
SSL_get_wfd() return the file
descriptors for the read or the write channel, which can be different. If
the read and the write channel are different,
will return the file descriptor of the read channel.
The following return values can occur:
The operation failed, because the underlying BIO is not of the correct type (suitable for file descriptors).
The file descriptor linked to ssl.
SSL_set_fd(3), ssl(3) , bio(3)