---
name: "SSL_flush_sessions"
section: "3ssl"
platform: "linux"
package: "libssl-doc"
version: "1.1.0l-1~deb9u1"
release: "Debian 9 (Stretch)"
platforms: ["linux"]
url: "https://carta.tech/man/SSL_CTX_flush_sessions"
---

# SSL\_flush\_sessions(3ssl)

remove expired sessions

Part of [SSL\_CTX\_flush\_sessions(3ssl)](/man/SSL_CTX_flush_sessions/3ssl.md).

## NAME

SSL\_CTX\_flush\_sessions, SSL\_flush\_sessions - remove expired sessions

## SYNOPSIS

```
 #include <openssl/ssl.h>
 void SSL_CTX_flush_sessions(SSL_CTX *ctx, long tm);
 void SSL_flush_sessions(SSL_CTX *ctx, long tm);
```

## DESCRIPTION

*SSL\_CTX\_flush\_sessions()* causes a run through the session cache of **ctx** to remove sessions expired at time **tm**.

*SSL\_flush\_sessions()* is a synonym for *SSL\_CTX\_flush\_sessions()*.

## NOTES

If enabled, the internal session cache will collect all sessions established up to the specified maximum number (see *SSL\_CTX\_sess\_set\_cache\_size()*). As sessions will not be reused ones they are expired, they should be removed from the cache to save resources. This can either be done\
  automatically whenever 255 new sessions were established (see *SSL\_CTX\_set\_session\_cache\_mode*(3)) or manually by calling *SSL\_CTX\_flush\_sessions()*.

The parameter **tm** specifies the time which should be used for the expiration test, in most cases the actual time given by *time*(0) will be used.

*SSL\_CTX\_flush\_sessions()* will only check sessions stored in the internal cache. When a session is found and removed, the remove\_session\_cb is however called to synchronize with the external cache (see *SSL\_CTX\_sess\_set\_get\_cb*(3)).

## SEE ALSO

[*ssl*(3)](/man/ssl/3.md), *SSL\_CTX\_set\_session\_cache\_mode*(3), *SSL\_CTX\_set\_timeout*(3), *SSL\_CTX\_sess\_set\_get\_cb*(3)

## COPYRIGHT

Copyright 2001-2016 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 \<https://www.openssl.org/source/license.html\>.