@node atan2
@section @code{atan2}
@findex atan2

POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9699919799/functions/atan2.html}

Gnulib module: atan2

Portability problems fixed by Gnulib:
@itemize
@end itemize

Portability problems not fixed by Gnulib:
@itemize
@end itemize