Linux 父进程创建子进程

#include 
#include 
#include 
int value = 5;
int count = 0;
int main()
{
    pid_t pid;

    pid = fork();
    if (pid == 0)
    {
        count ++;
        printf("count_pid0 = %dn",count);
        printf("child onen");
        printf("child twon");
        value = value + 15;
        printf("333n");
        
        count++;
        printf("count_pid0_second = %dn",count);
        return 0;
    }

    else if (pid > 0)
    {
    	count ++;
        printf("count_pid1 = %dn",count);
        printf("father onen");
        printf("father twon");
        
        wait(NULL);
        printf("value = %dn", value);
        return 0;
    }
}

总结：pid>0 为父进程，=0 为子进程；同时运行；先运行父进程，再运行子进程，如果父进程中用wait 则等待子进程运行完再运行父进程的后半部分。