On Sun, Mar 17, 2019 at 09:23:23PM -0400, Jerry Geis wrote:

I am trying to use the fnmatch() function in a C program and pass as the 3rd arg (options) of case insensitive search...

When I use the value FNM_CASEFOLD it does not work...

I'm confused on what to send to fnmatch() to do a case insensitive search.

Any pointers ? Thanks.

Depends on what you mean by "doesn't work". If you mean that you get a compile-time error:

cc -o foo foo.c foo.c: In function \u2018main\u2019: foo.c:20:35: error: \u2018FNM_CASEFOLD\u2019 undeclared (first use in this function) ret = fnmatch (argv[1], argv[2], FNM_CASEFOLD); ^ foo.c:20:35: note: each undeclared identifier is reported only once for each function it appears in

that's what I get too. The man page doesn't say anything about special requirements to use that function, but if you go look at fnmatch.h, you'll find:

#if !defined _POSIX_C_SOURCE || _POSIX_C_SOURCE < 2 || defined _GNU_SOURCE # define FNM_FILE_NAME FNM_PATHNAME /* Preferred GNU name. */ # define FNM_LEADING_DIR (1 << 3) /* Ignore `/...' after a match. */ # define FNM_CASEFOLD (1 << 4) /* Compare without regard to case. */ # define FNM_EXTMATCH (1 << 5) /* Use ksh-like extended matching. */ #endif

which indicates that those values aren't available UNLESS your program has defines matching the first line shown. I haven't bothered to check for the value of _POSIX_C_SOURCE in the absence of commandline options that change the GCC default behavior, but just defining _GNU_SOURCE is enough to make it compile:

[fredex@fcshome tmp]$ cc -o foo foo.c [fredex@fcshome tmp]$

foo.c:

#include <stdio.h> #include <stdlib.h>

#define _GNU_SOURCE #include <fnmatch.h>

int main (int argc, char ** argv) { int ret = 0;

if (argc != 3) { printf ("Oops. please specify two strings to compare\n"); exit (0); }

ret = fnmatch (argv[1], argv[2], FNM_CASEFOLD); printf ("fnmatch %s, %s returned %d\n", argv[1], argv[2], ret);

return 0; }

and running it results in:

$ ./foo abc abc fnmatch abc, abc returned 0

$ ./foo abc aBc fnmatch abc, aBc returned 0

$ ./foo abc aBcz fnmatch abc, aBcz returned 1