Portability problems fixed by Gnulib:
@itemize
@item
+The function @code{getopt_long_only} does not obey the combination of
+@samp{+} and @samp{:} flags in the options string on some platforms:
+glibc 2.11.
+@item
+The use of @samp{W;} in the optstring argument to does not always
+allow @code{-W foo} to behave synonymously with @code{--foo}:
+glibc 2.11.
+@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.
+Mac OS X 10.5, AIX 5.2, OSF/1 5.1, Solaris 10.
+@item
+The value of @code{optind} after a missing required argument is wrong
+on some platforms:
+Mac OS X 10.5.
@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.
+Mac OS X 10.5, OpenBSD 4.0, AIX 5.2, Solaris 11 2010-11, 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.
+Mac OS X 10.3, FreeBSD 5.2.1, NetBSD 5.0, Minix 3.1.8, AIX 5.1, HP-UX 11, IRIX 6.5,
+OSF/1 5.1, mingw, MSVC 9, Interix 3.5.
+@item
+This function crashes if the option string includes @code{W;} but
+there are no long options, on some platforms:
+glibc 2.14.
@end itemize
Portability problems not fixed by Gnulib:
@itemize
@item
-The glibc implementation allows a complete reset of the environment,
-including re-checking for @env{POSIXLY_CORRECT}, by setting
-@code{optind} to 0. Other implementations provide @code{optreset},
-causing a reset by setting it non-zero, although it does not
-necessarily re-read @env{POSIXLY_CORRECT}.
+Some implementations return success instead of reporting an ambiguity
+if user's option is a prefix of two long options with the same outcome:
+FreeBSD.
+@item
+The GNU Coding Standards discourage the use of @code{getopt_long_only}
+in new programs.
@end itemize