main.c

linux中管道的使用示例

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

int main(int argc, char **argv)
{
    int fd_pipe[2] = {-1};
    pid_t iChildProcessID = 0;
    char szReadPipeBuffer[200] = {0};
    char szCommandLineBuffer[200] = {0};
    char *pszCommandLineBuffer = NULL;

    if(argc == 1)
    {
        printf("Please input command:");
        if((pszCommandLineBuffer = gets(szCommandLineBuffer)) == NULL)
        {
            perror("gets");
            return EXIT_FAILURE;
        }
    }
    else
    {
        pszCommandLineBuffer = argv[1];
    }

    if(pipe(fd_pipe) < 0)
    {
        perror("pipe()");
    }
    else
    {
        iChildProcessID = fork();
        if(iChildProcessID < 0)
        {
            perror("fork()");
        }
        else if(iChildProcessID == 0)
        {
             close(fd_pipe[1]);
             fd_pipe[1] = -1;

             sleep(1);
             printf("In child process.\n");
             
             int iRet = read(fd_pipe[0],szReadPipeBuffer,200);
             if(iRet)
             {
                 printf("Executing \"%s\" ...\n",szReadPipeBuffer);
                 system(szReadPipeBuffer);

                 close(fd_pipe[0]);
                 fd_pipe[0] = -1;
             }
             else
             {
                 perror("read from pipe.");
             }
        }
        else
        {
             close(fd_pipe[0]);
             fd_pipe[0] = -1;
             //int iRet = write(fd_pipe[1],argv[1],strlen(argv[1]));     
             int iRet = write(fd_pipe[1],pszCommandLineBuffer,strlen(pszCommandLineBuffer));     
             if(iRet < 0)
             {
                 perror("write to pipe.");
             }
            
             sleep(2);

             iChildProcessID = wait(NULL);

             close(fd_pipe[1]);
             fd_pipe[1] = -1;
        }//if(fork())
    }//if(pipe(fd_pipe))...

/*
    close(fd_pipe[0]);
    fd_pipe[0] = -1;
    close(fd_pipe[1]);
    fd_pipe[1] = -1;
*/
    return EXIT_SUCCESS;

}