@subheading idn2_check_version
@anchor{idn2_check_version}
@deftypefun {const char *} {idn2_check_version} (const char * @var{req_version})
@var{req_version}: version string to compare with, or NULL.

Check IDN2 library version.  This function can also be used to read
out the version of the library code used.  See @code{IDN2_VERSION}  for a
suitable  @code{req_version} string, it corresponds to the idn2.h header
file version.  Normally these two version numbers match, but if you
are using an application built against an older libidn2 with a
newer libidn2 shared library they will be different.

Return value: 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 NULL if the
condition is not met.  If NULL is passed to this function no
check is done and only the version string is returned.
@end deftypefun

