Plan 9 from Bell Labs’s /usr/web/sources/plan9/sys/src/libc/9sys/getpid.c
#include <u.h> #include <libc.h> int getpid(void) { char b[20]; int f; memset(b, 0, sizeof(b)); f = open("#c/pid", 0); if(f >= 0) { read(f, b, sizeof(b)); close(f); } return atol(b); }