OSX: proc_pidinfo returns 0 for other user's processes

Question

I need to get some information (PID, UID, GID, process name) about running processes on Mac OSX. I tried proc_pidinfo. For my own processes it works fine. However,

Answer 1

I found that macOS Mojave (version 10.14.4) had struct proc_bsdshortinfo, which is a subset of struct proc_bsdinfo. You can get other user's processes without SUID by using it instead of struct proc_bsdinfo.

Well, I don't know from which version it is available.

edited: It is available since at least macOS 10.10.5 (Yosemite).
edited again: It may be available since Mac OS X 10.7 (Lion) because tmux uses struct proc_bsdshortinfo if __MAC_10_7 is defined. See here.

Example:

#include 
#include 
#include 

#include 

int main(int argc, char *argv[])
{
    pid_t pid;
    struct proc_bsdshortinfo proc;

    if (argc == 2)
        pid = atoi(argv[1]);
    else
        pid = getpid();

    int st = proc_pidinfo(pid, PROC_PIDT_SHORTBSDINFO, 0,
                         &proc, PROC_PIDT_SHORTBSDINFO_SIZE);

    if (st != PROC_PIDT_SHORTBSDINFO_SIZE) {
        fprintf(stderr, "Cannot get process info\n");
        return 1;
    }
    printf(" pid: %d\n", (int)proc.pbsi_pid);
    printf("ppid: %d\n", (int)proc.pbsi_ppid);
    printf("comm: %s\n",      proc.pbsi_comm);
    //printf("name: %s\n",      proc.pbsi_name);
    printf(" uid: %d\n", (int)proc.pbsi_uid);
    printf(" gid: %d\n", (int)proc.pbsi_gid);

    return 0;
}

This program prints:

$ ./pidinfo 
 pid: 3025
ppid: 250
comm: pidinfo
 uid: 501
 gid: 20
$ ./pidinfo 1
 pid: 1
ppid: 0
comm: launchd
 uid: 0
 gid: 0