---
name: "gnutls_sign_callback_set"
section: "3"
platform: "linux"
package: "gnutls-doc"
version: "3.3.8-6+deb8u7"
release: "Debian 8 (Jessie)"
platforms: ["linux"]
url: "https://new.carta.tech/gnutls_sign_callback_set"
---

# gnutls\_sign\_callback\_set(3)

API function

## NAME

gnutls\_sign\_callback\_set - API function

## SYNOPSIS

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

**void gnutls\_sign\_callback\_set(gnutls\_session\_t** *session***, gnutls\_sign\_func** *sign\_func***, void \*** *userdata***);**

## ARGUMENTS

- gnutls\_session\_t session

  is a gnutls session

- gnutls\_sign\_func sign\_func

  function pointer to application's sign callback.

- void \* userdata

  void pointer that will be passed to sign callback.

## DESCRIPTION

Set the callback function.  The function must have this prototype:

typedef int (\*gnutls\_sign\_func) (gnutls\_session\_t session, void \*userdata, gnutls\_certificate\_type\_t cert\_type, const gnutls\_datum\_t \* cert, const gnutls\_datum\_t \* hash, gnutls\_datum\_t \* signature);

The  *userdata* parameter is passed to the  *sign\_func* verbatim, and can be used to store application-specific data needed in the callback function.  See also **gnutls\_sign\_callback\_get()**.

## DEPRECATED

Use the PKCS 11 or **gnutls\_privkey\_t** interfacess like **gnutls\_privkey\_import\_ext()** instead.

## REPORTING BUGS

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

## COPYRIGHT

Copyright © 2001-2014 Free Software Foundation, Inc..\
 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

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