/* * Test of tracebacks from signal handlers. */#include <stdio.h>#include <signal.h>int catch(), secondcatch();main(){    signal(SIGQUIT, catch);    kill(getpid(), SIGQUIT);    printf("back in main\n");}catch(){    printf("in catch\n");    sigsetmask(0);    signal(SIGQUIT, secondcatch);    kill(getpid(), SIGQUIT);    printf("back in catch\n");}secondcatch(){    printf("in secondcatch\n");}