ref: e684b2a3fbd7d077ba4dabbd7fb4c7d1ff09c30c
dir: /sys/src/ape/lib/ap/plan9/getpgrp.c/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include "sys9.h"
#include "lib.h"
pid_t
getpgrp(void)
{
int n, f, pid;
char pgrpbuf[15], fname[30];
pid = getpid();
sprintf(fname, "/proc/%d/noteid", pid);
f = open(fname, 0);
n = read(f, pgrpbuf, sizeof pgrpbuf);
if(n < 0)
_syserrno();
else
n = atoi(pgrpbuf);
close(f);
return n;
}