@deftypefun {const char *} {gnutls_check_version} (const char * @var{req_version})
@var{req_version}: version string to compare with, or @code{NULL} .

Check the GnuTLS Library version against the provided string.
See @code{GNUTLS_VERSION}  for a suitable  @code{req_version} string.

See also @code{gnutls_check_version_numeric()} , which provides this
functionality as a macro.

@strong{Returns:} Check that the version of the library is at
minimum the one given as a string in  @code{req_version} and return the
actual version string of the library; return @code{NULL}  if the
condition is not met.  If @code{NULL}  is passed to this function no
check is done and only the version string is returned.
@end deftypefun