signal.c

#include "argcv/c/sys/signal.h"

#include <sys/types.h>  // pid_t

#include <stdio.h>  // printf

#include <signal.h>    // signal
#include <sys/wait.h>  // wait

sigfunc* _signal(int signo, sigfunc* func) {
  struct sigaction act;  // bits/sigaction.h
  struct sigaction oact;
  printf("signal called  ...\n");

  act.sa_handler = func;
  sigemptyset(&act.sa_mask);  // signal.h
  act.sa_flags = 0;

  if (signo == SIGALRM) {
#ifdef SA_INTERRUPT
    act.sa_flags |= SA_INTERRUPT;  // SunOS 4.x
#endif                             // SA_INTERRUPT
  } else {
#ifdef SA_RESTART
    act.sa_flags |= SA_RESTART;  // SVR4, 4.4BSD
#endif                           // SA_RESTART
  }
  if (sigaction(signo, &act, &oact) < 0) return SIG_ERR;
  return oact.sa_handler;
}

/**
 *
 */
void sig_chld(int signo) {
  pid_t pid;
  int stat;
  while ((pid = waitpid(-1, &stat, WNOHANG)) > 0) {
    // #ifdef __DEBUG__
    //     if (daemon_proc) {
    //       syslog(LOG_DEBUG, "child %d terminated \n", pid);
    //     } else {
    //       fprintf(stdout, "child %d terminated \n", pid);
    //     }
    // #endif  // __DEBUG__
  }
  return;
}

signal.h

#ifndef ARGCV_C_SYS_SIGNAL_H_
#define ARGCV_C_SYS_SIGNAL_H_

#ifdef __cplusplus
extern "C" {
#endif  //

// ref P. 105 , unix network programming
// ref : https://docs.oracle.com/cd/E19455-01/806-4750/signals-7/index.html
typedef void sigfunc(int);
sigfunc* _signal(int signo, sigfunc* func);
void sig_chld(int signo);

#ifdef __cplusplus
}
#endif  //

#endif  //  ARGCV_C_SYS_SIGNAL_H_