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gnulib/doc/posix-functions/getopt.texi
Eric Blake 3c8bb39bef test-getopt: test stderr behavior
Portions of this commit are commented out because they tickle
glibc bugs.  For a real-life example of the bug:

$ env -ua -:
env: invalid option -- :
Try `env --help' for more information.
$ env -:
env: invalid option -- :
Try `env --help' for more information.
$ env -+
env: invalid option -- +
Try `env --help' for more information.
$ env -ua -+
Try `env --help' for more information.

Notice that when -+ is not given as the first argument, the
error message is mistakenly suppressed.

* modules/getopt-posix-tests (Depends-on): Add dup2.
* tests/test-getopt.c (ASSERT): Avoid stderr.
(main): Move stderr to a temporary file.
* tests/test-getopt.h (getopt_loop): No longer manipulate opterr.
Instead, add parameter to inform caller if output occurred.
(test_getopt): Adjust all tests to expect silence, and add new
tests of leading ":".
* doc/glibc-functions/getopt_long.texi (getopt_long): Document
glibc shortcomings with leading "-:" or "+:" in optstring.
* doc/glibc-functions/getopt_long_only.texi (getopt_long_only):
Likewise.
* doc/posix-functions/getopt.texi (getopt): Likewise.

Signed-off-by: Eric Blake <ebb9@byu.net>
2009-12-22 06:44:00 -07:00

64 lines
2.4 KiB
Plaintext

@node getopt
@section @code{getopt}
@findex getopt
POSIX specification: @url{http://www.opengroup.org/onlinepubs/9699919799/functions/getopt.html}
Gnulib module: getopt-posix or getopt-gnu
The module @code{getopt-gnu} has support for ``long options'' and for
``options that take optional arguments''. Compared to the API defined by POSIX,
it adds a header file @code{<getopt.h>} and a function @code{getopt_long}.
Portability problems fixed by either Gnulib module @code{getopt-posix} or @code{getopt-gnu}:
@itemize
@item
The @code{getopt} function keeps some internal state that cannot be explicitly
reset on some platforms:
mingw.
@end itemize
Portability problems fixed by Gnulib module @code{getopt-gnu}:
@itemize
@item
The function @code{getopt} does not support the @samp{+} flag in the options
string on some platforms:
MacOS X 10.5, AIX 5.2, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 10.
@item
The function @code{getopt} does not obey the @samp{-} flag in the options
string when @env{POSIXLY_CORRECT} is set on some platforms:
Cygwin 1.7.0.
@item
The function @code{getopt} does not support options with optional arguments
on some platforms:
MacOS X 10.5, OpenBSD 4.0, AIX 5.2, HP-UX 11, IRIX 6.5, OSF/1 5.1,
Solaris 10, Cygwin 1.5.x.
@item
The function @code{getopt_long} is missing on some platforms:
AIX 5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 9, Interix 3.5.
@item
The function @code{getopt_long_only} 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, Solaris 9, mingw, Interix 3.5.
@end itemize
Portability problems not fixed by Gnulib:
@itemize
@item
The default behavior of the glibc implementation of @code{getopt} allows
mixing option and non-option arguments on the command line in any order.
Other implementations, such as the one in Cygwin, enforce strict POSIX
compliance: they require that the option arguments precede the non-option
arguments. This is something to watch out in your program's
testsuite.
@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}.
@item
Mixing a leading @samp{-} or @samp{+} with a leading @samp{:} in the
optstring argument has inconsistent effects across platforms.
@end itemize