Unix/Linux 信號處理示例程序

1.簡單的信號處理程序

1. #include <unistd.h>
2. #include <stdlib.h>
3. #include <stdio.h>
4. #include <signal.h>
6. static void sig_usr(int);
7. typedef void Sigfunc(int);
8. Sigfunc *signal(int,Sigfunc *);
10. int main(int argc,char **argv)
11. {
12. if(signal(SIGUSR1,sig_usr) == SIG_ERR){
13. fprintf(stderr,"Error!\n");
14. exit(-1);
15. }
16. if(signal(SIGUSR2,sig_usr) == SIG_ERR){
17. fprintf(stderr,"Error!\n");
18. exit(-1);
19. }
21. while(1)
22. pause();
23. }
25. static void sig_usr(int signo)
26. {
27. if(signo == SIGUSR1)
28. printf("received SIGUSR1!\n");
29. if(signo == SIGUSR2)
30. printf("received SIGUSR2!\n");
31. else
32. printf("received signal %d\n",signo);
33. }

後台執行，.然後使用kill命令來發送信號。

1. <strong>$ ./a.out &</strong>
2. [1] 7216
3. <strong>$ kill -USR1 7216
4. </strong>received SIGUSR1
5. <strong>$ kill -USR2 7216</strong>
6. received SIGUSR2
7. <strong>$ kill 7216
8. </strong>[1]+ Terminated ./a.out

2.調用不可重入函數的示例程序

1. #include <unistd.h>
2. #include <stdlib.h>
3. #include <stdio.h>
4. #include <signal.h>
6. typedef void Sigfunc(int);
7. Sigfunc *signal(int,Sigfunc *);
9. static void my_alarm(int signo)
10. {
11. struct passwd *rootptr;
13. printf("in signal handle\n");
14. if((rootptr = getpwnam("root")) == NULL){
15. printf("error!\n");
16. exit(-1);
17. }
18. alarm(1);
19. }
20. int main(int argc,char **argv)
21. {
22. struct passwd *ptr;
24. signal(SIGALRM,my_alarm);
25. alarm(1);
26. for(;;){
27. if((ptr = getpwnam("leon")) == NULL)
28. err_sys("getpwnam error");
29. if(strcmp(ptr->pw_name,"leon") != 0)
30. printf("return value corrupted!,pw_name = %s\n",ptr->pw_name);
31. }
32. }