IPC 有命管道
创建一个有名管道 /tmp/stduent.data
A 和 B 是 相对独立的两支程序，现在 A 传送 10 个Student 到 B
B 将Student 读取出来，显示在界面上
然后 B 传送 10 个 Teacher 到 A ，A 显示 teacher 在界面上
A.cpp
#include "public.h"
#define FIFO_NAME "/temp/Linux/my_fifo"
#define BUFFER_SIZE PIPE_BUF
#define TEN_MEG (1024*1024*10)
typedef struct students
{
int no;
char username[100];
}*StuNode,SNode;
int main()
{
int pipe_fd;
int ret;
int open_mode=O_WRONLY;
int bytes=0;
char buffer[BUFFER_SIZE+1];
SNode stus[10];
for (int i=0;i<10;i++)
{
stus[i].no=i+1;
strcpy(stus[i].username,"student");
}
if (access(FIFO_NAME,F_OK)==-1)
{
ret=mkfifo(FIFO_NAME,0777);
if (ret!=0)
{
fprintf(stderr,"Could not create fifo %s\n",FIFO_NAME);
exit(EXIT_FAILURE);
}
}
printf("Process %d opening FIFO O_WRONLY\n",getpid());
pipe_fd=open(FIFO_NAME,open_mode);
printf("Process %d result %d\n",getpid(),pipe_fd);
if (pipe_fd!=-1)
{
while (bytes<10)
{
ret=write(pipe_fd,&stus[bytes],sizeof(SNode));
if (ret==-1)
{
fprintf(stderr,"write error on pipe\n");
exit(EXIT_FAILURE);
}
bytes++;
}
close(pipe_fd);
}
else
{
exit(EXIT_FAILURE);
}
printf("Process %d finish \n",getpid());
exit(EXIT_FAILURE);
return 0;
}
B.cpp
#include "public.h"
#define FIFO_NAME "/temp/Linux/my_fifo"
#define BUFFER_SZIE PIPE_BUF
typedef struct students
{
int no;
char username[100];
}*StuNode,SNode;
int main()
{
int pipe_fd;
int ret;
int open_mode=O_RDONLY;
char buffer[BUFFER_SZIE+1];
int bytes=0;
SNode stus[10];
memset(buffer,'\0',sizeof(buffer));
printf("Process %d opening FIFO O_RDONLY\n",getpid());
pipe_fd=open(FIFO_NAME,open_mode);
if (pipe_fd!=-1)
{
do
{
ret=read(pipe_fd,&stus[bytes],sizeof(SNode));
printf("no = %d username = %s \n",stus[bytes].no,stus[bytes].username);
bytes++;
} while (ret>0);
close(pipe_fd);
}
else
exit(EXIT_FAILURE);
printf("Process %d finished,%d bytes read\n",getpid(),bytes);
exit(EXIT_FAILURE);
return 0;
}