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I'm playing with fork in linux and i see something that don't like me

I read this link After forking, are global variables shared? and i did a test with gdb


[c0m0@worktux programming]$ ps aux | grep env


c0m0      3108  0.0  0.0   4288   324 pts/1    S    22:53   0:00 ./env
c0m0      3110  0.0  0.0   4288    80 pts/1    S    22:53   0:00 ./env



[c0m0@worktux programming]$ gdb -q -p 3108
Attaching to process 3108



(gdb) call getenv("toto")
$1 = 4195989
(gdb) x/s $1
0x400695:   "root"

Now i'll attach to child process

[c0m0@worktux programming]$ gdb -q -p 3110

Attaching to process 3110

(gdb) call getenv("toto")

$1 = 4195989

(gdb) x/s $1

0x400695: "root"

So my what my question is, why i see the variable what i set into fork in the both process?

I used the function putenv for set toto=root, i try to be more clear.

Can i see a environment variable that was setting in the child process from the parent?

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  • You mean you called `putenv` and then `fork`? Then of course both of them have the same variable set. – Carl Norum Jul 18 '13 at 21:58
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    The answer is still valid, the `fork` function duplicate the process memory (and some other resources like file descriptors) at the time of the fork. This include environment variables. – Sylvain Defresne Jul 18 '13 at 21:59
  • I used putenv with fork() { putenv("toto=root"); }, so i know the child receive a copy of parent resources, but i would like to know if enviroment variables of the child process are shared with the parent. – c4f4t0r Jul 19 '13 at 06:58
  • Even after your edit, it seems to me that the other question answers this one: No, you can't unless you implement something. – madth3 Jul 19 '13 at 15:34

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