fusl/src/signal/sigisemptyset.c

#define _GNU_SOURCE
#include <signal.h>
#include <string.h>

int sigisemptyset(const sigset_t* set) {
  static const unsigned long zeroset[_NSIG / 8 / sizeof(long)];
  return !memcmp(set, &zeroset, _NSIG / 8);
}