linux进程控制开发实例

fork.c

#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    pid_t result;
    
    result = fork();
    
    if (result == -1)
    {
        printf("Fork Error!
");
    }
    else
    {
        if (result == 0)
        {
            printf("The returned value is %d
The child process!!
My PID is %d
", result, getpid());
        }
        else
        {
            printf("The returned value is %d
The father process!!
My PID is %d
", result, getpid());
        }
    }
    
    return 0;
}

exec.c

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    pid_t result;
    
    result = fork();
    
    if (result == 0)
    {
        if (execlp("ps", "ps", "-ef", NULL) < 0)
        {
            printf("Execlp error
");
        }
    }
    
    return 0;
}

waitpid.c

#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    pid_t pc, pr;
    
    pc = fork();
    
    if (pc < 0)
    {
        printf("Error fork
");
    }
    else if (pc == 0)
    {
        sleep(5);
        exit(0);
    }
    else
    {
        do
        {
            pr = waitpid(pc, NULL, WNOHANG);
            
            if(pr == 0)
            {
                printf("The child process has not exited!
");
                sleep(1);
            }
        }while (pr == 0);
        
        if (pr == pc)
        {
            printf("Get child exit code: %d
", pr);
        }
        else
        {
            printf("Some error occured.
");
        }
    }
    
    return 0;
}

参考资料：《嵌入式Linux应用程序开发标准教程》