5 POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9699919799/functions/getopt.html}
7 LSB specification:@* @url{https://refspecs.linuxbase.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/libutil-getopt-3.html}
9 Gnulib module: getopt-posix or getopt-gnu
11 The module @code{getopt-gnu} has support for ``long options'' and for
12 ``options that take optional arguments''. Compared to the API defined by POSIX,
13 it adds a header file @code{<getopt.h>} and a function @code{getopt_long}.
15 Portability problems fixed by either Gnulib module @code{getopt-posix} or @code{getopt-gnu}:
18 This function is missing on some platforms:
21 The value of @code{optind} after a missing required argument is wrong
23 Mac OS X 10.13, AIX 7.1, mingw.
26 Portability problems fixed by Gnulib module @code{getopt-gnu}:
29 The function @code{getopt} does not support the @samp{+} flag in the options
30 string on some platforms:
31 Mac OS X 10.13, AIX 5.2, HP-UX 11, IRIX 6.5, Solaris 11 2010-11.
33 The function @code{getopt} does not obey the combination of @samp{+}
34 and @samp{:} flags in the options string on some platforms:
37 The function @code{getopt} does not obey the @samp{-} flag in the options
38 string when @env{POSIXLY_CORRECT} is set on some platforms:
41 The function @code{getopt} does not support options with optional arguments
43 Mac OS X 10.13, OpenBSD 4.0, AIX 5.2, HP-UX 11, IRIX 6.5, Solaris 11 2010-11, Cygwin 1.5.x.
45 The function @code{getopt_long} is missing on some platforms:
46 AIX 5.1, HP-UX 11, IRIX 6.5, Solaris 9, MSVC 14.
48 The function @code{getopt_long} does not support abbreviated long options
49 where all disambiguations are equivalent on some platforms:
52 The function @code{getopt_long_only} is missing on some platforms:
53 FreeBSD 5.2.1, NetBSD 9.0, AIX 5.1, HP-UX 11, IRIX 6.5, Solaris 9, mingw, MSVC 14.
55 This function crashes if the option string includes @code{W;} on some
60 Portability problems not fixed by Gnulib:
63 The default behavior of the glibc implementation of @code{getopt} allows
64 mixing option and non-option arguments on the command line in any order.
65 Other implementations, such as the one in Cygwin, enforce strict POSIX
66 compliance: they require that the option arguments precede the non-option
67 arguments. This is something to watch out in your program's
70 The glibc implementation allows a complete reset of the environment,
71 including re-checking for @env{POSIXLY_CORRECT}, by setting
72 @code{optind} to 0. Several BSD implementations provide @code{optreset},
73 causing a reset by setting it non-zero, although it does not
74 necessarily re-read @env{POSIXLY_CORRECT}. Solaris @code{getopt} does
75 not support either reset method, but does not maintain state that
76 needs the extra level of reset.
78 On some platforms, this function does not set the stream error
79 indicator on attempts to write to a read-only stream:
80 glibc 2.13, Cygwin 1.7.9.