Hi there,
I'm seeing something I don't quite understand concerning environment
variables. (This is on an OpenBSD 4.2 amd64 system) I hope someone here
can explain.
Given the following C-program:
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
int main(int argc, char **argv)
{
char *var1 = "FOO=TESTING";
int rc;
sleep(10);
rc = putenv(var1);
if (rc < 0) {
printf("Error inserting <%s> in environ, errno = %d\n",
var1, errno);
return 1;
}
printf("<%s> inserted in environ\n", var1);
sleep(10);
return 0;
}
In another terminal, I start a while loop:
$ while true ; do ps -eww | grep F[O]O ; sleep 1 ; done
When I run this program using "env -i ./a.out", the while loop
in the other terminal doesn't show any output at all. ps doesn't
seem to see FOO being put in the environment.
However, when I start the program using "env -i FOO=BAR ./a.out", the
while loop in the other terminal shows this output, beginning right after
the start of the program:
20571 p2 I+ 0:00.00 FOO=BAR (a.out)
20571 p2 I+ 0:00.00 FOO=BAR (a.out)
20571 p2 I+ 0:00.00 FOO=BAR (a.out)
20571 p2 I+ 0:00.00 FOO=BAR (a.out)
20571 p2 I+ 0:00.00 FOO=BAR (a.out)
20571 p2 I+ 0:00.00 FOO=BAR (a.out)
20571 p2 I+ 0:00.00 FOO=BAR (a.out)
20571 p2 I+ 0:00.00 FOO=BAR (a.out)
20571 p2 I+ 0:00.00 FOO=BAR (a.out)
20571 p2 I+ 0:00.00 FOO=BAR (a.out)
20571 p2 I+ 0:00.00 FOO=TESTING (a.out)
20571 p2 I+ 0:00.00 FOO=TESTING (a.out)
20571 p2 I+ 0:00.00 FOO=TESTING (a.out)
20571 p2 I+ 0:00.00 FOO=TESTING (a.out)
20571 p2 I+ 0:00.00 FOO=TESTING (a.out)
20571 p2 I+ 0:00.00 FOO=TESTING (a.out)
20571 p2 I+ 0:00.00 FOO=TESTING (a.out)
20571 p2 I+ 0:00.00 FOO=TESTING (a.out)
20571 p2 I+ 0:00.00 FOO=TESTING (a.out)
20571 p2 I+ 0:00.00 FOO=TESTING (a.out)
So ps does show FOO, *and* it shows the value of FOO changing after
ten seconds.
I don't understand this behaviour. On another system (AIX), ps does pick
up newly set environment variables. Is this behaviour implementation
dependent?
Thanks,
--
Jurjen Oskam
Savage's Law of Expediency:
You want it bad, you'll get it bad.
