Something

#include  <stdio.h>
#include  <signal.h>
#include  <sys/types.h>



void sighand(int);


int  main(void)
{
        struct sigaction act;

        bzero(&act, sizeof(act));

        act.sa_handler = sighand;
        act.sa_flags = SA_NOMASK | SA_NODEFER;

        printf("%d\n",sigaction(SIGUSR1, &act, NULL));

        signal(SIGUSR1, sighand);
        raise(SIGUSR1);
        while (1)
             pause();
}

void  sighand(int sig)
{
        printf(".");
        fflush(stdout);
        raise(SIGUSR1);
        while (1);
}