content/2021-05-15-pthread_cancel-noexcept/thread.cc


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// file   : thread.cc
// compile: g++ thread.cc -o thread -lpthread

#include <atomic>

#include <pthread.h>
#include <unistd.h>

struct S {
    ~S() {
        const char msg[] = "cancellation-point\n";
        // write() -> pthread cancellation point.
        write(STDOUT_FILENO, msg, sizeof(msg));
    }
};

std::atomic<bool> gReleaseThread{false};

void* threadFn(void*) {
    while (!gReleaseThread) {}

    // Hit cancellation point in destructor which
    // is implicitly `noexcept`.
    S s;

    return nullptr;
}

int main() {
    pthread_t t;
    pthread_create(&t, nullptr /* attr */, threadFn, nullptr /* arg */);

    // Cancel thread and release it to hit the cancellation point.
    pthread_cancel(t);
    gReleaseThread = true;

    pthread_join(t, nullptr /* retval */);

    return 0;
}