Date: Sun, 20 Oct 1996 20:56:37 -0600 (MDT) From: Marc Slemko <marcs@znep.com> To: Ron Bolin <rlb@mindspring.com> Cc: freebsd-current@FreeBSD.org Subject: Re: mktemp BUG? Message-ID: <Pine.BSF.3.95.961020205133.15603G-100000@alive.ampr.ab.ca> In-Reply-To: <326AD788.167EB0E7@mindspring.com>
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Check the man page for mktemp:
>NOTES
> A common problem that results in a core dump is that the programmer pass-
> es in a read-only string to mktemp() or mkstemp(). This is common with
> programs that were developed before ISO 9899: 1990 (``ISO C'') compilers
> were common. For example, calling mkstemp() with an argument of
> "/tmp/tempfile.XXXXXX" will result in a core dump due to mkstemp() at-
> tempting to modify the string constant that was given. If the program in
> question makes heavy use of that type of function call, you do have the
> option of compiling the program so that it will store string constants in
> a writable segment of memory. See gcc(1) for more information.
Try something like:
#include <unistd.h>
#include <stdio.h>
int main () {
char *tmp;
char filename[80];
strcpy(filename, "/tmp/cp.XXXXX");
tmp = mktemp(filename);
printf("file: %s (%p, %p)\n", tmp, tmp, filename);
return 0;
}
Yes, mktemp is a bit strange.
On Sun, 20 Oct 1996, Ron Bolin wrote:
> Just checking my system and sanity. The mktemp(char *) function
> dumps core everytime. Seems to be a problem in the C lib version.
> Can anyone else duplicate this bug?
> #include <stdlib.h>
> char *tmp = mktemp("/tmp/cp.XXXXXX");
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