在liunxC下的编程求解
1.有三个进程
2.其中一个进程等待其它两个进程的信号，当两个来了就打印出一句“Engine is running”
3.另外两个进程每隔10秒向上一个进程发信号，并且打印“Oil is ready” “Power is on”

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

void process_start()
{
pid_t oil_process;
pid_t power_process;
if((oil_process=fork())==0)
{
sleep(10);
kill(engine_process,SIGUSR1);
printf("Oil is ready\n");
exit(0);
}
if((power_process=fork())==0)
{
sleep(10);
kill(engine_process,SIGUSR2);
printf("Power is on\n");
exit(0);
}
}


static void sig_usr(int signo)
{
if((signo==SIGUSR1) && (signo==SIGUSR2))
{
printf("Engine is running \n");
}
}

main(void)
{
struct sigaction act;
act.sa_handler=sig_usr;
act.sa_flags=0;

pid_t engine_process;

sigaction(SIGUSR1,&act,NULL);
sigaction(SIGUSR2,&act,NULL);

if((engine_process=fork())==0)
{
process_start();
exit(0);
}
}
直接写的，求纠正！

[解决办法]

C/C++ code

static void sig_usr(int signo){    static unsigned char s_flags = 0x00;    if (signo == SIGUSR1)    {        s_flags |= 0x01;    }    else if (signo == SIGUSR2))    {        s_flags |= 0x02;    }    if (0x03 == (s_flags & 0x03))    {        s_flags = 0x00;        printf("Engine is running \n");    }}
[解决办法]
太可怕了。。。 代码到你们这里就变的那么不可控。。。能自己看看man手册吗- -。。

这个代码我测过了，可以正常工作。

C/C++ code
#include <stdio.h>#include <stdlib.h>#include <string.h>#include <signal.h>#include <unistd.h>#include <sys/types.h>#include <sys/wait.h>void sig_handler(int signo) {        switch (signo) {                case SIGUSR1:                        fprintf(stderr, "A is ready\n");                        break;                case SIGUSR2:                        fprintf(stderr, "B is ready\n");                        break;                default:                        break;        }}int main(int argc, char* const argv[]) {        struct sigaction act;        sigset_t mask;        bzero(&act, sizeof(act));        sigemptyset(&mask);        sigaddset(&mask, SIGUSR2);        act.sa_handler = sig_handler;        act.sa_mask = mask;        if (sigaction(SIGUSR1, &act, NULL) == -1) {                fprintf(stderr, "ERROR:sigaction SIGUSR1\n");                return -1;        }        sigemptyset(&mask);        sigaddset(&mask, SIGUSR1);        act.sa_mask = mask;        if (sigaction(SIGUSR2, &act, NULL) == -1) {                fprintf(stderr, "ERROR:sigaction SIGUSR2\n");                return -1;        }        int ndx;        for (ndx = 0; ndx != 2; ++ ndx) {                pid_t pid;                int sig[2] = {SIGUSR1, SIGUSR2};                if ((pid = fork()) == -1) {                        fprintf(stderr, "ERROR:fork\n");                        return -1;                } else if (pid == 0) {                        int times = 0;                        for ( ; times != 5; ++ times) {                                kill(getppid(), sig[ndx]);                                sleep(10);                        }                        exit(0);                }        }        int ret;        pid_t pid;        for (ret = 0; ret != 2; ) {                pid = wait(NULL);                if (pid != -1) {                        ++ ret;                }        }        return 0;}