| @node optopt | |
| @section @code{optopt} | |
| @findex optopt | |
| POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9699919799/functions/optopt.html} | |
| Gnulib module: --- | |
| Portability problems fixed by Gnulib: | |
| @itemize | |
| @end itemize | |
| Portability problems not fixed by Gnulib: | |
| @itemize | |
| @item | |
| This variable is missing on some platforms: | |
| Mac OS X 10.5, IRIX 6.5, MSVC 14. | |
| @end itemize |