SSL_SET_SESSION(3) | Library Functions Manual | SSL_SET_SESSION(3)

# NAME

`SSL_set_session` — set a TLS/SSL session to be used during TLS/SSL connect

# SYNOPSIS

library “libssl” libcrypto
`#include <openssl/ssl.h>`

int
`SSL_set_session`(SSL *ssl, SSL_SESSION *session);

# DESCRIPTION

`SSL_set_session`() sets session to be used when the TLS/SSL connection is to be established. `SSL_set_session`() is only useful for TLS/SSL clients. When the session is set, the reference count of session is incremented by 1. If the session is not reused, the reference count is decremented again during `SSL_connect`(). Whether the session was reused can be queried with the SSL_session_reused(3) call.

If there is already a session set inside ssl (because it was set with `SSL_set_session`() before or because the same ssl was already used for a connection), SSL_SESSION_free(3) will be called for that session.

SSL_SESSION objects keep internal link information about the session cache list when being inserted into one SSL_CTX object's session cache. One SSL_SESSION object, regardless of its reference count, must therefore only be used with one SSL_CTX object (and the SSL objects created from this SSL_CTX object).

# RETURN VALUES

The following return values can occur:

0
  The operation failed; check the error stack to find out the reason.
1
  The operation succeeded.

# SEE ALSO

ssl(3), SSL_CTX_set_session_cache_mode(3), SSL_get_session(3), SSL_SESSION_free(3), SSL_session_reused(3)

# HISTORY

`SSL_set_session`() first appeared in SSLeay 0.5.2 and has been available since OpenBSD 2.4.

June 8, 2025 | Debian