如何从C ++调用sigaction

Question

I know how to use it in C (with signal.h), but the <csignal> library is provided in C++ and I want to know if it includes sigaction? I tried running it but it said not found. I was wondering if I did something wrong?

#include <iostream>
#include <string>
#include <cstdio>
#include <csignal>

namespace {
  volatile bool quitok = false;
  void handle_break(int a) {
    if (a == SIGINT) quitok = true;
  }
  std::sigaction sigbreak;
  sigbreak.sa_handler = &handle_break;
  sigbreak.sa_mask = 0;
  sigbreak.sa_flags = 0;
  if (std::sigaction(SIGINT, &sigbreak, NULL) != 0) std::perror("sigaction");
}

int main () {
  std::string line = "";
  while (!::quitok) {
    std::getline(std::cin, line);
    std::cout << line << std::endl;
  }
}

But for some reason it doesn't work. EDIT: By "doesn't work", I mean the compiler fails and says there's no std::sigaction function or struct.

sigaction is C POSIX isn't it?

Answer 1

sigaction is in POSIX, not the C++ standard, and it's in the global namespace. You'll also need the struct keyword to differentiate between sigaction , the struct, and sigaction , the function. Finally, the initialization code will need to be in a function -- you can't have it in file scope.

#include <cstdio>
#include <signal.h>

namespace {
  volatile sig_atomic_t quitok = false;
  void handle_break(int a) {
    if (a == SIGINT) quitok = true;
  }
}

int main () {
  struct sigaction sigbreak;
  sigbreak.sa_handler = &handle_break;
  sigemptyset(&sigbreak.sa_mask);
  sigbreak.sa_flags = 0;
  if (sigaction(SIGINT, &sigbreak, NULL) != 0) std::perror("sigaction");
  //...
}