[SOLVED] Why does wait() set status to 255 instead of the -1 exit status of the forked process?

Why does wait() set status to 255 instead of the -1 exit status of the forked process?

I'm trying to return an integer value from a child process.

However, if I use exit(1) I get 256 as the output from wait(). Using exit(-1) gives 65280.

Is there a way I can get the actual int value that I send from the child process?

if(!(pid=fork()))
{
    exit(1);
}
waitpid(pid,&status,0);
printf("%d",status);

Edit: Using exit(-1) (which is what I actually want) I am getting 255 as the output for WEXITSTATUS(status). Is it supposed to be unsigned?

Solution

Have you tried "man waitpid"?

The value returned from the waitpid() call is an encoding of the exit value. There are a set of macros that will provide the original exit value. Or you can try right shifting the value by 8 bits, if you don't care about portability.

The portable version of your code would be:

if(!(pid=fork()))
{
    exit(1);
}
waitpid(pid,&status,0);
if (WIFEXITED(status)) {
    printf("%d", WEXITSTATUS(status));
}