SSL_get_fd, SSL_get_rfd, SSL_get_wfd - get file descriptor linked to an SSL object

#include <openssl/ssl.h>

int SSL_get_fd(const SSL *ssl);
int SSL_get_rfd(const SSL *ssl);
int SSL_get_wfd(const SSL *ssl);

SSL_get_fd() returns the file descriptor which is linked to ssl. SSL_get_rfd() and 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, SSL_get_fd() 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(7) , bio(7)

Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (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

2021-03-25 1.1.1k