Signal handler that uses pthread_sigmask and sigwait.
- C++17
- Clang or GCC
- linux
- pthread
- cmake (recommended, but optional)
- Catch2 for testing
{
// Block signals
sgnl::SignalHandler signal_handler({SIGINT, SIGTERM});
// Wait for a signal
int signal_number = signal_handler.sigwait();
// Or, pass a handler
auto handler = [](int signum) {
if( signum == SIGINT )
// continue waiting for signals
return false;
if( signum == SIGTERM )
// stop waiting for signals
return true;
};
int last_signal = signal_handler.sigwait_handler(handler);
} // signals are unblocked again
Using a condition variable to shutdown all threads:
#include <sgnl/AtomicCondition.h>
#include <sgnl/SignalHandler.h>
#include <cstdlib>
#include <future>
#include <iostream>
#include <thread>
void Worker(const sgnl::AtomicCondition<bool>& exit_condition)
{
auto predicate = [&exit_condition]() {
return exit_condition.get();
};
while( true )
{
exit_condition.wait_for(std::chrono::minutes(1), predicate);
if( exit_condition.get() )
return;
/* ... do work ... */
}
}
int main()
{
sgnl::AtomicCondition<bool> exit_condition(false);
auto handler = [&exit_condition](int signum) {
std::cout << "received signal " << signum << "\n";
if( signum == SIGTERM || signum == SIGINT )
{
exit_condition.set(true);
// wakeup all waiting threads
exit_condition.notify_all();
// stop polling for signals
return true;
}
// continue waiting for signals
return false;
};
// Block signals in this thread.
// Threads spawned later will inherit the signal mask.
sgnl::SignalHandler signal_handler({SIGINT, SIGTERM, SIGUSR1});
std::future<int> ft_sig_handler =
std::async(
std::launch::async,
&sgnl::SignalHandler::sigwait_handler,
&signal_handler,
std::ref(handler));
std::vector<std::future<void>> futures;
for(int i = 0; i < 10; ++i)
futures.push_back(
std::async(
std::launch::async,
Worker,
std::ref(exit_condition)));
// SIGUSR1
std::this_thread::sleep_for(std::chrono::milliseconds(100));
kill(0, SIGUSR1);
// SIGTERM
kill(0, SIGTERM);
std::this_thread::sleep_for(std::chrono::milliseconds(100));
for(auto& future : futures)
future.wait();
int last_signal = ft_sig_handler.get();
std::cout << "exiting (received signal " << last_signal << ")\n";
return EXIT_SUCCESS;
}
mkdir -p build/ && cd build/
cmake ..
# build and run tests
make sgnl-test && ./test/sgnl-test
# build and run example
make example && ./example
# install headers and CMake config
make install