fork with stdout buffer

main.c

// https://twitter.com/RhoP_nim/status/676667506052825090
#include "apue.h"

int glob = 6;
char buf[] = "a write to stdout\n";

void err_sys(const char *x, ...)
{
  perror(x);
  exit(1);
}

int main(void)
{
  int var;
  pid_t pid;
  var = 88;

  if(write(STDOUT_FILENO, buf, sizeof(buf)-1) != sizeof(buf)-1) err_sys("write error");

  printf("before fork\n");
  /* added */
  fflush(stdout);

  if((pid = fork()) < 0) {
    err_sys("fork error");
  } else if(pid == 0) {
    glob++;
    var++;
  } else {
    sleep(2);
  }
  printf("pid = %d, glod = %d, var = %d\n", getpid(), glob, var);
  exit(0);
}