watki.c

#include <pthread.h>
#include <unistd.h>
#include <sys/types.h>
#include <stdio.h>
#include <signal.h>
#include <string.h>

pthread_t tid;

typedef struct data
{
 char name[10];
 int age;
}data;

void sig_func(int sig)
{
 pthread_kill(tid,SIGUSR1);
 pthread_join(tid,NULL);
 signal(SIGUSR1, SIG_IGN);
}

void func(data *p)
{
 strcpy(p->name,"rado rado!");
 p->age=31;
 if(sleep(15) == 0) { // Sleep to catch the signal
    fprintf(stderr, "No sig - override\n");
    strcpy(p->name,"Mr. SIGNAL");
    p->age=1;
 }
}

int main()
{

 pthread_attr_t attr;
 data d;
 data *ptr = &d;
 int sleep_time = 20;

 signal(SIGUSR1,sig_func); // Register signal handler before going multithread
 pthread_attr_init(&attr);
 pthread_create(&tid,&attr,(void*)func,ptr);
 while((sleep_time = sleep(sleep_time)) > 0){
    fprintf(stderr, "Still %d seconds to end\n", sleep_time);
    signal(SIGUSR1,sig_func);
 }
 fprintf(stderr, "Name:%s\n",ptr->name);
 fprintf(stderr, "Age:%d\n",ptr->age);

 return 0;
}