---
name: "gnutls_dh_get_prime_bits"
section: "3"
platform: "linux"
package: "gnutls"
version: "3.8.13-3"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/gnutls_dh_get_prime_bits"
---

# gnutls\_dh\_get\_prime\_bits(3)

API function

## NAME

gnutls\_dh\_get\_prime\_bits - API function

## SYNOPSIS

**#include \<gnutls/gnutls.h\>**

**int gnutls\_dh\_get\_prime\_bits(gnutls\_session\_t** *session***);**

## ARGUMENTS

- gnutls\_session\_t session

  is a gnutls session

## DESCRIPTION

This function will return the bits of the prime used in the last Diffie-Hellman key exchange with the peer.  Should be used for both anonymous and ephemeral Diffie-Hellman.  Note that some ciphers, like RSA and DSA without DHE, do not use a Diffie-Hellman key exchange, and then this function will return 0.

## RETURNS

The Diffie-Hellman bit strength is returned, or 0 if no Diffie-Hellman key exchange was done, or a negative error code on failure.

## REPORTING BUGS

Report bugs to \<bugs@gnutls.org\>.\
 Home page: https://www.gnutls.org

## COPYRIGHT

Copyright © 2001-2023 Free Software Foundation, Inc., and others.\
 Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved.

## SEE ALSO

The full documentation for **gnutls** is maintained as a Texinfo manual. If the /usr/share/doc/gnutls/ directory does not contain the HTML form visit

- https://www.gnutls.org/manual/