@deftypefun {const char *} {stringprep_check_version} (const char * @var{req_version}) @var{req_version}: Required version number, or NULL. Check that the the version of the library is at minimum the requested one and return the version string; return NULL if the condition is not satisfied. If a NULL is passed to this function, no check is done, but the version string is simply returned. See @code{STRINGPREP_VERSION} for a suitable @code{req_version} string. @strong{Return value:} Version string of run-time library, or NULL if the run-time library does not meet the required version number. @end deftypefun