Bind callback functions to OS signals in C and C++.
SigFn should work in any system with the standard C library,
which provides the <signal.h> header.
SigFn usage is similar to the os/signal package from Golang.
Basic SigFn usage in C. It is copied from pause.c in the
examples directory.
#include <sigfn.h>
#include <stdio.h>
// to implement sleep_for()
#ifdef _WIN32
#include <Windows.h>
#else
#include <time.h>
#endif
// signal handler
static void handle_signal(int signum, void *userdata);
// helper function to abstract platform dependent sleep functions
static void sleep_for(int ms);
int main()
{
// used to store signum
int flag;
// initialize to what should be an impossible value for SIGINT
flag = -1;
// set callback for SIGINT
sigfn_handle(SIGINT, handle_signal, &flag);
// notify user that the program is "paused"
puts("Paused. Press Ctrl+C to exit.");
// sleep loop until we receive the signal
while (flag < 0)
{
// this should stop the CPU from being overworked
sleep_for(100);
}
// notify user that flag was set and exit cleanly
printf("\nReceived signal: %d\n", flag);
return 0;
}
void handle_signal(int signum, void *userdata)
{
// set int that was passed by address
*(int*)userdata = signum;
}
void sleep_for(int ms)
{
#ifdef _WIN32
Sleep(ms);
#else
const struct timespec duration = {
.tv_sec = ms / 1000,
.tv_nsec = (ms % 1000) * 1000000,
};
nanosleep(&duration, NULL);
#endif
}Basic SigFn usage in C++. It is copied from pause.cpp in the
examples directory.
#include <sigfn.hpp>
#include <iostream>
#include <thread>
int main(int argc, const char **argv)
{
bool loop;
// set callback for SIGINT
sigfn::handle(SIGINT, [&](int signum) {
std::cout << std::endl << "Received signal: " << signum << std::endl;
loop = false;
});
// notify user that the program is "paused"
std::cout << "Paused. Press Ctrl+C to exit." << std::endl;
// sleep loop until we receive the signal
loop = true;
while(loop)
{
// sleep for 100ms
std::this_thread::sleep_for(std::chrono::milliseconds(100));
}
return 0;
}