在ac程序中运行shell命令

Question

我想在我的c程序中运行一个shell命令.但事实是,我不想让我的程序等到命令执行.无需读取shell命令的输出(它无论如何都不返回数据)所以基本上,这可能吗？

Answer 1

fork()而system()这正是你所需要的

Answer 2

当然,只是fork和exec:用于fork创建一个新进程,并在子进程中使用exec命令启动shell.execv获取通常给shell的参数.

您的代码可能如下所示:

pid_t child_pid = fork();
if (child_pid == 0)
{   // in child
    /* set up arguments */
    // launch here
    execv("/bin/sh", args);
    // if you ever get here, there's been an error - handle it
}
else if (child_pid < 0)
{   // handle error
}

子进程SIGCHLD在死亡时会发出信号.从POSIX标准(SUSv4)引用的代码将处理:

static void
handle_sigchld(int signum, siginfo_t *sinfo, void *unused)
{
    int status;

    /*
     * Obtain status information for the child which
     * caused the SIGCHLD signal and write its exit code
     * to stdout.
    */
    if (sinfo->si_code != CLD_EXITED)
    {
        static char msg[] = "wrong si_code\n";
        write(2, msg, sizeof msg - 1);
    }
    else if (waitpid(sinfo->si_pid, &status, 0) == -1)
    {
        static char msg[] = "waitpid() failed\n";
        write(2, msg, sizeof msg - 1);
    }
    else if (!WIFEXITED(status))
    {
        static char msg[] = "WIFEXITED was false\n";
        write(2, msg, sizeof msg - 1);
    }
    else
    {
        int code = WEXITSTATUS(status);
        char buf[2];
        buf[0] = '0' + code;
        buf[1] = '\n';
        write(1, buf, 2);
    }
}