* bug in cygwin's gcc/g++ getopt_long(): erroneous "ambiguous option"
@ 2009-01-13 6:14 Dan Tsafrir
2009-01-13 13:06 ` Corinna Vinschen
0 siblings, 1 reply; 2+ messages in thread
From: Dan Tsafrir @ 2009-01-13 6:14 UTC (permalink / raw)
To: cygwin
Hi,
When given certain long options, Cygwin's getopt_long() function
erroneously fails on "ambiguous option". The short program below
illustrates the problem: getopt_long() wrongfully reports the "--xy"
option as ambiguous.
Strangely, if flipping the order of the 2nd and 3rd entries in the
options-array (by compiling the program with -DNO_BUG) the bug goes
away, clearly demonstrating inconsistent Cygwin/getopt_long behavior.
The bug is triggered when compiling the program with Cygwin's default
gcc/g++ (3.4.4) or with gcc-4/g++-4 (4.3.2). The bug does not occur
when compiling the program with gcc/g++ (ver 3 or 4) on other OSes
(e.g., Linux).
A fix would be appreciated.
Best,
--Dan
// start program:
#include <stdio.h>
#include <getopt.h>
const struct option lopts[] = {
#ifdef NO_BUG
{"xy1" , required_argument, NULL, 'a' },
{"xy" , required_argument, NULL, 'b' },
{"xy2" , required_argument, NULL, 'c' },
{NULL , 0 , NULL, 0 },
#else /* swapping order of 2nd and 3rd entries generates the bug */
{"xy1" , required_argument, NULL, 'a' },
{"xy2" , required_argument, NULL, 'c' },
{"xy" , required_argument, NULL, 'b' },
{NULL , 0 , NULL, 0 },
#endif
};
int main()
{
const char* argv[] = {"./a", "--xy=1", NULL};
int argc = 2;
int index, c;
// if NO_BUG defined, will print: "got opt=b" [OK]
// otherwise: "a: ambiguous option -- xy" [BUG]
if( (c = getopt_long(argc, (char**)argv, "A:B:C", lopts, &index)) != EOF )
printf("got opt=%c\n", c);
return 0;
}
// end program
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: bug in cygwin's gcc/g++ getopt_long(): erroneous "ambiguous option"
2009-01-13 6:14 bug in cygwin's gcc/g++ getopt_long(): erroneous "ambiguous option" Dan Tsafrir
@ 2009-01-13 13:06 ` Corinna Vinschen
0 siblings, 0 replies; 2+ messages in thread
From: Corinna Vinschen @ 2009-01-13 13:06 UTC (permalink / raw)
To: cygwin
On Jan 13 00:49, Dan Tsafrir wrote:
> Hi,
>
> When given certain long options, Cygwin's getopt_long() function
> erroneously fails on "ambiguous option". The short program below
> illustrates the problem: getopt_long() wrongfully reports the "--xy"
> option as ambiguous.
>
> Strangely, if flipping the order of the 2nd and 3rd entries in the
> options-array (by compiling the program with -DNO_BUG) the bug goes
> away, clearly demonstrating inconsistent Cygwin/getopt_long behavior.
> [...]
> #include <stdio.h>
> #include <getopt.h>
>
> const struct option lopts[] = {
> #ifdef NO_BUG
> {"xy1" , required_argument, NULL, 'a' },
> {"xy" , required_argument, NULL, 'b' },
> {"xy2" , required_argument, NULL, 'c' },
> {NULL , 0 , NULL, 0 },
> #else /* swapping order of 2nd and 3rd entries generates the bug */
> {"xy1" , required_argument, NULL, 'a' },
> {"xy2" , required_argument, NULL, 'c' },
> {"xy" , required_argument, NULL, 'b' },
> {NULL , 0 , NULL, 0 },
> #endif
> };
>
> int main()
> {
> const char* argv[] = {"./a", "--xy=1", NULL};
> int argc = 2;
> int index, c;
>
> // if NO_BUG defined, will print: "got opt=b" [OK]
> // otherwise: "a: ambiguous option -- xy" [BUG]
> if( (c = getopt_long(argc, (char**)argv, "A:B:C", lopts, &index)) != EOF )
> printf("got opt=%c\n", c);
>
> return 0;
> }
This appears to be a bug in the upstream version of getopt we're
using in Cygwin, which is the latest version from OpenBSD. I'm
looking into creating a patch for Cygwin 1.7.
Thanks for the report,
Corinna
--
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Project Co-Leader cygwin AT cygwin DOT com
Red Hat
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