fifo

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fifo_write.c

#include <sys/types.h>

#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define FIFO "/tmp/myfifo"

main(int argc,char** argv)
{
  /*参数为即将写入的字节数*/
  int fd;
  char w_buf[100];
  int nwrite;
  if(fd==-1)
  {
      if(errno)
      {
          printf("open error; no reading process\n");
      }
  }
  /*打开FIFO管道，并设置非阻塞标志*/
  fd=open(FIFO,O_WRONLY|O_NONBLOCK,0);
  if(argc==1)
  {
      printf("Please send something\n");
  }
  strcpy(w_buf,argv[1]);
  /*向管道中写入字符串*/
  if((nwrite=write(fd,w_buf,100))==-1)
  {
      if(errno==EAGAIN)
      {

printf("The FIFO has not been read yet. Please try later\n"

      }
  }
  else
  {
      printf("write %s to the FIFO\n",w_buf);
  }
}

fifo_read.c

#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define FIFO "/tmp/myfifo"

main(int argc,char** argv)
{
  /*参数为即将写入的字节数*/
  int fd;
  char buf_r[100];
  int nread;

  /*创建有名管道，并设置相应的权限*/
  if((mkfifo(FIFO,O_CREAT|O_EXCL)<0)&&(errno!=EEXIST))
  {
      printf("cannot creat fifoserver\n");
  }
  printf("Preparing for reading bytes\n");
memset(buf_r,0,sizeof(buf_r));
/*打开有名管道，并设置非阻塞标志*/
fd=open(FIFO,O_RDONLY|O_NONBLOCK,0);
if(fd==-1)
{
      perror("open====");
exit(1);
}
while(1)
{
memset(buf_r,0,sizeof(buf_r));
if((nread=read(fd,buf_r,100))==-1)
{
if(errno==EAGAIN)
{

printf("no data yet\n");
}
}
printf("read %s from FIFO\n",buf_r);
sleep(1);
}
pause();
unlink(FIFO);

}

运行结果：

Preparing for reading bytes
read from FIFO
read from FIFO
read from FIFO
read Helloo from FIFO
read from FIFO

...