test10_5.txt

linux under the C programming which complementary with the book of <linux under the C programming

#include <stdio.h>
#include <signal.h>
#include <errno.h>

void checkmask(void);

int main(void)
{
    	char buffer[100];
    	sigset_t blockset, sigset;
    	int errno_backup;

	errno_backup=errno;
	sigemptyset(&blockset);


    	sigaddset(&blockset,SIGTSTP);
    	sigaddset(&blockset,SIGINT);
	sigprocmask(SIG_SETMASK,&blockset,NULL);
	checkmask();
	printf("press any key to continue");
	getchar();

	sigaddset(&blockset,SIGTERM);
	sigprocmask(SIG_BLOCK,&blockset,NULL);
	checkmask();
	printf("press any key to continue");
	getchar();

    	sigdelset(&blockset,SIGINT);
	sigprocmask(SIG_UNBLOCK,&blockset,NULL);
	checkmask();
	printf("press any key to continue");
	getchar();
}
	
	void checkmask(void)
        {
	  if(sigprocmask(0,NULL,&sigset)<0)
	  {
		printf("Sigprocmask error");
		errno=errno_backup;
		exit(0);
	  }
	printf("signal mask:");
	if(sigismember(&sigset,SIGINT)
		printf("SIGint");

	if(sigismember(&sigset,SIGTSTP)
		printf("SIGTSTP");

	if(sigismember(&sigset,SIGTERM)
		printf("SIGTERM");
	printf("\n");
	
	errno=errno_backup;
	}