To temporarily block SIGCHLD:

      
  sigset_t sset;
  sigset_t oldset;
  
  sigemtpyset(&sset);
  sigaddset(&sset, SIGCHLD);
      sigprocmask(SIG_BLOCK, &sset, 0);
      ...
      sigprocmask(SIG_UNBLOCK, &sset, 0);