mprocess.c

来自「周立功magic2200实验箱linux增补例子。包括（GPIO zlg7290」· C语言 代码 · 共 65 行

#include "config.h"
//#include <unistd.h>

#define LED   16    // P2.16 controles LED1
#define BEEP  7    // P0.7 controles BEEP

int main(void)
{
    int fd, fd2;
    uint32 val;
    pid_t child;

    fd = open("/dev/P0", O_RDONLY);
    if(fd == -1)
    {
        printf("\nCan't open P0!\n");
        exit(-1);
    }

    fd2 = open("/dev/P2", O_RDONLY);
    if(fd == -1)
    {
        printf("\nCan't open P2!\n");
        exit(-1);
    }

    ioctl(fd, GPIO_SET_PIN_OUT, BEEP);
    ioctl(fd2, GPIO_SET_PIN_OUT, LED);
    ioctl(fd, GPIO_SET_PIN, BEEP);
    ioctl(fd2, GPIO_SET_PIN, LED);

    printf("\nTry to create new process.\n");

    child = vfork();

    switch(child)
    {
        case -1:  // fault
            perror("vfork error\n");
            exit(-1);

        case 0:    // child process
        {
            printf("This is child, BEEP is running\n");
            ioctl(fd, GPIO_CLR_PIN, BEEP);
            sleep(1);
            ioctl(fd, GPIO_SET_PIN, BEEP);
            sleep(1);
            exit(0);
        } 
        default:  // father process
        {
            printf("This is father, LED is lighting.\n");
            while(1)
            {
                ioctl(fd2, GPIO_CLR_PIN, LED);
                sleep(1);
                ioctl(fd2, GPIO_SET_PIN, LED);
                sleep(1);
            }
        }
    }
    return 0;
}