writing to closed stdout (II): exit status

[kdevel]

On Sunday, 15 December 2024 at 17:16:11 UTC, Paul Backus wrote:
> It's possible to get the full exit status from `waitid` [3],

Actually not on my linux machine:

```C
$ cat status.c
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

int main ()
{
    int rc = fork ();
    assert (rc != -1);
    if (rc == 0) /* child */
       _exit (-1);
    else {
       siginfo_t si;
       waitid (P_ALL, 0, &si, WEXITED);
       printf ("%x\n", si.si_status);
    }
    return 0;
}
$ cc status.c
$ ./a.out
ff
```

But your reference [3] does not say that it should. Also [4] only 
says that the lower 8 bit constitute the the corresponding part 
of si_status. Not more not less. Likewise the code on SO [5] does 
not yield more than 8 bits here on my linux box.

[4] 
https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_13

[5] 
https://stackoverflow.com/questions/179565/exit-codes-bigger-than-255-possible