From: "Dan Tsafrir" <dan.tsafrir@gmail.com>
To: cygwin@cygwin.com
Subject: bug in cygwin's gcc/g++ getopt_long(): erroneous "ambiguous option"
Date: Tue, 13 Jan 2009 06:14:00 -0000 [thread overview]
Message-ID: <b2c39fcb0901122149j1f3057adhaa600ea21fe7156c@mail.gmail.com> (raw)
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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next reply other threads:[~2009-01-13 5:50 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-13 6:14 Dan Tsafrir [this message]
2009-01-13 13:06 ` Corinna Vinschen
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