Linux下简单管道测试


read.c

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#define W "/tmp/myfifo"
int main()
{
        if(mkfifo(W, O_CREAT | O_EXCL) < 0)
        {
                printf("mkfifo fail!\n");
                exit(1);
        }
        int fd;
        if((fd = open(W,O_RDONLY | O_NONBLOCK ,0))< 0)           //在创建管道的进程中我没法以只写方式打开管道文件,会返回-1.
        {
                printf("open %s fail!\n", W);
                exit(1);
        }
        char buff[1024];
        memset(buff, 0, sizeof(buff));
        int read_num;
        while(1)
        {
                if((read_num = read(fd, buff, 1024))<=0)          //在write.c没有打开管道文件时,read_num为0,当write.c打开管道文件后且没有输入时,read_nu                                       //m为-1;
                        printf("no data yet!\n");
                else{
                        printf("%s\n", buff);
//                      break;
                }
                sleep(1);

        }
        unlink(W);
}
write.c
#include <stdlib.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#define FIFO "/tmp/myfifo"
#include <string.h>

int main()
{
        int fd;
        fd=open(FIFO, O_WRONLY | O_NONBLOCK, 0);
        if(fd == -1)
        {
                printf("open %s fail!\n",FIFO);
                exit(1);
        }
        char write_buff[1024];                //可以将数组赋值给指针,但是不能将指针赋值给数组,会报错!
        memset(write_buff, \0, sizeof(char)*1024);      
        gets(write_buff);                  //此处用scanf会因为空格而导致输入结束
        int write_num= write(fd,write_buff, 1024 );
}

 

  

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