细说linux IPC（六）：pipe和FIFO

标签：ipc   pipe   fifo   

      #include <unistd.h>
       int pipe(int pipefd[2]);

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


int main(int argc, char *argv[])
{
   int pipefd[2];
   pid_t cpid;
   char buf[128];
   int readlen;


   if (argc != 2) {
        fprintf(stderr, "Usage: %s <string>\n", argv[0]);
        return -1;
   }
   if (pipe(pipefd) < 0) {
       fprintf(stderr, "pipe: %s\n", strerror(errno));
       return -1;
   }
   cpid = fork();
   if (cpid < 0) {
       fprintf(stderr, "fork: %s\n", strerror(errno));
       return -1;
   }
   if (0 == cpid) { /* 子进程 */
       close(pipefd[1]); /* 子进程关闭写端 */
       readlen = read(pipefd[0], buf, 128); //子进程阻塞在读上，等待父进程写
       if (readlen < 0) {
            fprintf(stderr, "read: %s\n", strerror(errno));
            return -1;
       }
       write(STDOUT_FILENO, buf, readlen);
       write(STDOUT_FILENO, "\n", 1);
       close(pipefd[0]); //读完之后关闭读描述符
       return 0;
   } else { /* 父进程 */
       close(pipefd[0]); /*父进程关闭没用的读端 */
       sleep(2);
       write(pipefd[1], argv[1], strlen(argv[1])); //父进程开始写
       close(pipefd[1]); /* 父进程关闭写描述符 */
       wait(NULL); /* 父进程等待子进程退出，回收子进程资源 */
       return 0;
   }
}

       #include <sys/types.h>
       #include <sys/stat.h>
       int mkfifo(const char *pathname, mode_t mode);

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include "slnipc.h"
int main(int argc, const char *argv[])
{
    int rc;
    int wr_fd, rd_fd;
    char sendbuf[128];
    char recvbuf[128];
    rc = mkfifo(SLN_IPC_2SER_PATH, O_CREAT | O_EXCL); //建立服务进程读的fifo
    if ((rc < 0 ) && (errno != EEXIST)) {
        fprintf(stderr, "mkfifo: %s\n", strerror(errno));
        return -1;
    }
    rc = mkfifo(SLN_IPC_2CLT_PATH, O_CREAT | O_EXCL); //建立服务进程写的fifo
    if ((rc < 0 ) && (errno != EEXIST)) {
        fprintf(stderr, "mkfifo: %s\n", strerror(errno));
        return -1;
    }
    wr_fd = open(SLN_IPC_2CLT_PATH, O_RDWR, 0);
    if (wr_fd < 0) {
        fprintf(stderr, "open: %s\n", strerror(errno));
        return -1;
    }
    rd_fd = open(SLN_IPC_2SER_PATH, O_RDWR, 0);
    if (rd_fd < 0) {
        fprintf(stderr, "open: %s\n", strerror(errno));
        return -1;
    }
    for (;;) {
        rc = read(rd_fd, recvbuf, sizeof(recvbuf)); //循环等待接受客户进程数据
        if (rc < 0) {
            fprintf(stderr, "read: %s\n", strerror(errno));
            continue;
        }
        printf("server recv: %s\n", recvbuf);
        snprintf(sendbuf, sizeof(sendbuf), "Hello, this is server!\n");
        rc = write(wr_fd, sendbuf, strlen(sendbuf));
        if (rc < 0) {
            fprintf(stderr, "write: %s\n", strerror(errno));
            continue;
        }
    }
    close(wr_fd);
    close(rd_fd);
    return 0;
}

#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include "slnipc.h"
int main(int argc, const char *argv[])
{
    int rc;
    int rd_fd, wr_fd;
    char recvbuf[128];
    char sendbuf[128];
    if (argc != 2) {
        fprintf(stderr, "Usage: %s <string>\n", argv[0]);
        return -1;
    }
    snprintf(sendbuf, sizeof(sendbuf), "%s", argv[1]);
    wr_fd = open(SLN_IPC_2SER_PATH, O_RDWR, 0);
    if (wr_fd < 0) {
        fprintf(stderr, "open: %s\n", strerror(errno));
        return -1;
    }
    rd_fd = open(SLN_IPC_2CLT_PATH, O_RDWR, 0);
    if (rd_fd < 0) {
        fprintf(stderr, "open: %s\n", strerror(errno));
        return -1;
    }
    rc = write(wr_fd, sendbuf, strlen(sendbuf));
    if (rc < 0) {
        fprintf(stderr, "write: %s\n", strerror(errno));
        return -1;
    }
    rc = read(rd_fd, recvbuf, sizeof(recvbuf));
    if (rc < 0) {
        fprintf(stderr, "write: %s\n", strerror(errno));
        return -1;
    }
    printf("client read: %s\n", recvbuf);
    close(wr_fd);
    close(rd_fd);
    return 0;
}

# ./server 
server recv: hi,this is fifo client 


# ./client "hi,this is fifo client" 
client read: Hello, this is server! 

本节源码下载：

http://download.csdn.net/detail/gentleliu/8183027

细说linux IPC（六）：pipe和FIFO

标签：ipc   pipe   fifo   

原文地址：http://blog.csdn.net/shallnet/article/details/41346743