---
name: "SSL_CTX_flush_sessions"
section: "3ssl"
platform: "linux"
package: "openssl"
version: "3.6.5-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/SSL_CTX_flush_sessions"
---

# SSL\_CTX\_flush\_sessions(3ssl)

remove expired sessions

## NAME

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

## SYNOPSIS

```
 #include <openssl/ssl.h>
 void SSL_CTX_flush_sessions_ex(SSL_CTX *ctx, time_t tm);
```

The following functions have been deprecated since OpenSSL 3.4, and can be hidden entirely by defining **OPENSSL\_API\_COMPAT** with a suitable version value, see **openssl\_user\_macros**(7):

```
 void SSL_CTX_flush_sessions(SSL_CTX *ctx, long tm);
```

## DESCRIPTION

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

**SSL\_CTX\_flush\_sessions()** is an older variant of the function that is not Y2038 safe due to usage of long datatype instead of time\_t.

## 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\_ex()**.

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\_ex()** 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)).

## RETURN VALUES

**SSL\_CTX\_flush\_sessions\_ex()** does not return a value.

## SEE ALSO

[**ssl**(7)](/ssl/7.md), **SSL\_CTX\_set\_session\_cache\_mode**(3), **SSL\_CTX\_set\_timeout**(3), **SSL\_CTX\_sess\_set\_get\_cb**(3)

## HISTORY

**SSL\_CTX\_flush\_sessions\_ex()** was added in OpenSSL 3.4.

## COPYRIGHT

Copyright 2001-2024 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (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\>.