UNIX环境高级编程1.9信号

// program 1-9 proc/shell2.c
#include "apue.h"
#include <sys/wait.h>

static void sig_int(int); /* our signal-catching function */

int main(void)
{
    char buf[MAXLINE]; /* from apue.h */
    pid_t pid;
    int status;

    if (signal(SIGINT, sig_int) == SIG_ERR)
    {
        err_sys("signal error");
    }

    printf("%% "); /* print prompt (printf requires %% to print %) */
    while (fgets(buf, MAXLINE, stdin) != NULL)
    {
        if (buf[strlen(buf) - 1] == '
')
        {
            buf[strlen(buf) - 1] = 0; /* replace newline with null */
        }

        if ((pid = fork()) < 0)
        {
            err_sys("fork error");
        }
        else if (pid == 0)
        { /* child */
            execlp(buf, buf, (char *)0);
            err_ret("couldn't execute: %s", buf);
            exit(127);
        }

        /* parent */
        if ((pid = waitpid(pid, &status, 0)) < 0)
        {
            err_sys("waitpid error");
        }
        printf("%% ");
    }
    return 0;
}

void sig_int(int signo)
{
    printf("interrupt
%% ");
}

all: shell1 shell2
shell1: shell1.c
	g++ -g -Wall shell1.c ../lib/libapue.a -I ../include -o shell1
shell2: shell2.c
	g++ -g -Wall shell2.c ../lib/libapue.a -I ../include -o shell2
clean:
	rm shell1 shell2