有名管道的应用实例，创建两个有名管道实现全双工通信，两个进程间的聊天

创建两个有名管道来实现不同进程间的全双工通信。

两个进程聊天程序：一个server端，一个client端。

例子用到了read函数：

read函数只是一个通用的读文件设备的接口。是否阻塞需要由设备的属性和设定所决定。一般来说，读字符终端、网络的socket描述字，管道文件等，这些文件的缺省read都是阻塞的方式。

如果是读磁盘上的文件，一般不会是阻塞方式的。但使用锁和fcntl设置取消文件O_NOBLOCK状态，也会产生阻塞的read效果。

server端：

 

#include <stdio.h> #include <unistd.h> #include <strings.h> #include <string.h> #include <stdlib.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h>


#define FIFO_WRITE "readfifo"
#define FIFO_READ "writefifo"
#define LEN       300

int main(int argc, char* argv[]) { char buf[LEN]; char readbuf[LEN]; int wfd; int rfd; int len; mkfifo(FIFO_WRITE, S_IFIFO|0666); rfd = open(FIFO_READ, O_RDONLY); wfd = open(FIFO_WRITE, O_WRONLY); while(1) { bzero(readbuf, LEN); len = read(rfd, readbuf, LEN); printf("len=%d\n", len); if (len > 0) { readbuf[len] = '\0'; printf("client: %s\n", readbuf); if (strncmp("quit", readbuf, strlen(readbuf)) == 0) { break; } } bzero(buf, LEN); printf("server: "); fgets(buf, LEN, stdin); buf[strlen(buf)-1] = '\0'; write(wfd, buf, strlen(buf)); } close(wfd); unlink(FIFO_WRITE); close(rfd); return 0; }

 

 

 

client端：

 

#include <stdio.h> #include <unistd.h> #include <strings.h> #include <string.h> #include <stdlib.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h>


#define FIFO_READ "readfifo"
#define FIFO_WRITE "writefifo"
#define LEN       300

int main(int argc, char* argv[]) { char buf[LEN]; char readbuf[LEN]; int wfd; int rfd; int len; mkfifo(FIFO_WRITE, S_IFIFO|0666); wfd = open(FIFO_WRITE, O_WRONLY); rfd = open(FIFO_READ, O_RDONLY); while(1) { bzero(buf, LEN); printf("client: "); fgets(buf, LEN, stdin); buf[strlen(buf)-1] = '\0'; write(wfd, buf, strlen(buf)); printf("buf:%s\n", buf); if (strncmp("quit", buf, strlen(buf)) == 0) { break; } bzero(readbuf, LEN); len = read(rfd, readbuf, LEN); if (len > 0) { readbuf[len] = '\0'; printf("server: %s\n", readbuf); } } close(wfd); unlink(FIFO_WRITE); close(rfd); return 0; }