fork_handler.h

volatile uint64_t MAIN_THREAD_ID = 0;
volatile int8_t MAIN_THREAD_ID_SET = 0;

typedef void (*OnForkHandler)();

OnForkHandler __forkHandler = NULL;

/* Auxiliary function to call global fork handler if defined.

Note: Fork handler needs to be in C (not cython) otherwise it would require
GIL to be present, but some forks can exec non-python processes.
*/
void handleAtFork(void) {
    // Reset the MAIN_THREAD_ID on fork, because the main thread ID is not
    // always the same after fork, especially when forked from within a thread.
    MAIN_THREAD_ID_SET = 0;

    if (__forkHandler != NULL) {
        __forkHandler();
    }
}


void setForkHandler(OnForkHandler handler)
{
    __forkHandler = handler;
}


void resetForkHandler(void)
{
    __forkHandler = NULL;
}

void setMainThreadID(uint64_t id) {
    MAIN_THREAD_ID = id;
    MAIN_THREAD_ID_SET = 1;
}