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)
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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 https://www.openssl.org/source/license.html.