c - Stuck with sigwait -

i did wrong in code, other process send sigusr2 signal it:

sigset_t sigset; sigemptyset(&sigset); sigaddset(&sigset, sigill); sigaddset(&sigset, sigusr2); sigwait(&sigset, &received); 

xcode notices siguser2(31) signal received, received = sigill(4) (or minimal signal in set).

why so? wrong?

now, looks this:

    sigset_t sigset;     sigemptyset(&sigset);     sigaddset(&sigset, sigill);     sigaddset(&sigset, sigusr2);     sigprocmask(sig_block, &sigset, 0);     sigwait(&sigset, &received);     if(received == sigusr2) {         //...     } else if(received == sigill) {         //...     } 

still not working.

sometimes debugger can in way. have seen debuggers interfere signal handling before. try running code without debugger involved.

the following code works on os x:

#include <signal.h> #include <stdio.h>  int main() {     sigset_t set;     int sig;      sigemptyset(&set);     sigaddset(&set, sigusr1);     sigaddset(&set, sigusr2);     sigprocmask(sig_block, &set, null);     sigwait(&set, &sig);     printf("got signal %d\n", sig);     return 0; }