@node getopt_long_only
@subsection @code{getopt_long_only}
@findex getopt_long_only

Gnulib module: getopt-gnu

Portability problems fixed by Gnulib:
@itemize
@item
The function @code{getopt_long_only} does not support the @samp{+}
flag in the options string on some platforms:
MacOS X 10.5, AIX 5.2, OSF/1 5.1, Solaris 10.
@item
The function @code{getopt_long_only} does not obey the @samp{-} flag
in the options string when @env{POSIXLY_CORRECT} is set on some platforms:
Cygwin 1.7.0.
@item
Some implementations fail to reset state, including re-checking
@env{POSIXLY_CORRECT}, when @code{optind} is set to @samp{0}:
NetBSD, Cygwin 1.7.0.
@item
The function @code{getopt_long_only} does not support options with
optional arguments on some platforms:
MacOS X 10.5, OpenBSD 4.0, AIX 5.2, Solaris 10, Cygwin 1.5.x.
@item
This function is missing on some platforms:
MacOS X 10.3, FreeBSD 5.2.1, NetBSD 3.0, AIX 5.1, HP-UX 11, IRIX 6.5,
OSF/1 5.1, mingw, Interix 3.5.
@end itemize

Portability problems not fixed by Gnulib:
@itemize
@item
The glibc extension of using @samp{W;} in the optstring argument to
allow @code{-W foo} to behave synonymously with @code{--foo} is not
very reliable.
@item
Some implementations return success instead of reporting an ambiguity
if user's option is a prefix of two long options with the same flag:
FreeBSD.
@item
Mixing a leading @samp{-} or @samp{+} with a leading @samp{:} in the
optstring argument has inconsistent effects across platforms.
@end itemize
