How to allow non-option arguments in any order to getopt?

Question

I have a C program which expects to be called with several options and 1 non-option argument (i.e. with no associated option letter), and uses getopt to parse these options. For example, it could be called with:

Example1: myProgram -a "aParam" -b "bParam" "xParam"

I have been using SLES10, and the options worked in any order. For example, the non-option argument, "xParam" could come first:

Example2: myProgram "xParam" -a "aParam" -b "bParam"

However, when testing in SLES11, it seems that getopt stops processing as soon as it reaches a non-option parameter, so example 2 above does not work.

I've read the getopt man pages and seen that this may be relevant:

If the first character of optstring is '+' or the environment variable POSIXLY_CORRECT is set, then option processing stops as soon as a nonoption argument is encountered.

I'm not sure if SLES11 sets POSIXLY_CORRECT by default. What is the best way to get the old SLES10 getopt behaviour in SLES11?

type `set` on the terminal (unix etc) to see if POSIXLY_CORRECT is set, perhaps? — William Morris, Nov 08 '12 at 14:29
`$ set | grep "POSIXLY_CORRECT"` doesn't return anything, so maybe it is not set. — DBPaul, Nov 08 '12 at 14:52
Are you sure you have `getopt.h` included explicitly from your sources? — alk, Nov 08 '12 at 16:26
@WilliamMorris: `env` is a better way than `set` to inspect the environment. — Fred Foo, Nov 08 '12 at 16:35
@larsmans: system dependent perhaps? For me (MacOS) `env` gives a subset of `set` (28 against 58 variables). — William Morris, Nov 08 '12 at 18:42
@WilliamMorris: `set` prints the shell variables (and functions), which are indeed a superset of the environment variables. Only environment variables are passed to child processes. — Fred Foo, Nov 08 '12 at 21:05

score 1 · Accepted Answer · edited May 11 '16 at 13:09

1

It turns out that by default it was redirecting to _posix_getopt(), which was causing the behaviour I described above.

The possible solutions I found to this in the end:

Use getopt_long() instead. This doesn't seem to have a posix equivalent.
Define _GNU_SOURCE, which stops the redirection.
Manually reorder the parameters, possibly using a wrapper shell script.

edited May 11 '16 at 13:09

Matt Caton

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answered Nov 15 '12 at 20:46

DBPaul

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Apologies for the trivial edit - only way I could remove my accidental downvote (and turn it into an upvote). – Matt Caton May 11 '16 at 13:10

How to allow non-option arguments in any order to getopt?

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