Linux系统编程：客户端-服务器用FIFO进行通信

先放下代码  回来在解释

头文件：

clientinfo.h

 struct CLIENTINFO{
     char myfifo[];
     int leftarg;
     int rightarg;
     char op;
 };
 typedef struct CLIENTINFO CLIENTINFO, *CLINTINFOPTR;

client.c

 #include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
 #include <fcntl.h>
 #include <signal.h>
 #include "clientinfo.h"

 #define FIFO_NAME "/home/levi/chatapplication/data/server_fifo/chat_server_fifo"
 #define BUFF_SZ 100

 char mypipename[BUFF_SZ];
 void handler(int sig){
     unlink(mypipename);
     exit();
 }

 int main(int argc, char const *argv[])
 {
     int res;
     int fifo_fd, my_fifo;
     int fd;
     CLIENTINFO info;
     char buffer[BUFF_SZ];

     signal(SIGKILL, handler);
     signal(SIGINT, handler);
     signal(SIGTERM, handler);

     if(argc != ){
         printf("Usage: %s op1 operation op2\n", argv[]);
         exit();
     }
     if(access(FIFO_NAME, F_OK) == -){
         printf("Could not open FIFO %s\n", FIFO_NAME);
         exit(EXIT_FAILURE);
     }
     fifo_fd = open(FIFO_NAME, O_WRONLY);
     if(fifo_fd == -){
         printf("Could not open %s for write access\n", FIFO_NAME);
         exit(EXIT_FAILURE);
     }
     sprintf(mypipename, "/home/levi/chat_client_%d_fifo", getpid());
     res = mkfifo(mypipename, );
     if(res != ){
         printf("FIFO %s was not created\n", buffer);
         exit(EXIT_FAILURE);
     }

     my_fifo = open(mypipename, O_RDONLY | O_NONBLOCK);
     if(my_fifo == -){
         printf("Could not open %s for read only access\n", FIFO_NAME);
         exit(EXIT_FAILURE);
     }

     strcpy(info.myfifo, mypipename);
     info.leftarg = atoi(argv[]);
     info.op = argv[][];
     info.rightarg = atoi(argv[]);

     write(fifo_fd, &info, sizeof(CLIENTINFO));
     close(fifo_fd);

     memset(buffer, '\0', BUFF_SZ);
     while(){
         res = read(my_fifo, buffer, BUFF_SZ);
         if(res > ){
             printf("Received from server : %s\n", buffer);
             break;
         }
     }
     printf("Client %d is terminating\n", getpid());
     close(my_fifo);
     (void)unlink(mypipename);
     return ;
 }

server.c

 #include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
 #include <fcntl.h>
 #include <signal.h>
 #include "clientinfo.h"

 #define FIFO_NAME "/home/levi/server_fifo/chat_server_fifo"
 void handler(int sig){
     unlink(FIFO_NAME);
     exit();
 }

 int calc(CLIENTINFOPTR info){
     switch(info->op){
         case '+' : return info->leftarg + info->rightarg;
         case '-' : return info->leftarg - info->rightarg;
         case '*' : return info->leftarg * info->rightarg;
         case '/' : return info->leftarg / info->rightarg;
     }
     return ;
 }

 int main(int argc, char const *argv[])
 {
     int res, i, fifo_fd, fd1;
     CLIENTINFO info;
     char buffer[];
     signal(SIGKILL, handler);
     signal(SIGINT, handler);
     signal(SIGTERM, handler);
     if(access(FIFO_NAME, F_OK) == -){
         res = mkfifo(FIFO_NAME, );
         if(res != ){
             printf("FIFO %s was not created\n", FIFO_NAME);
             exit(EXIT_FAILURE);
         }
     }
     fifo_fd = open(FIFO_NAME, O_RDONLY);
     if(fifo_fd == -){
         printf("Could not open %s for read only access\n", FIFO_NAME);
         exit(EXIT_FAILURE);
     }
     printf("\nServer is rarin to go !\n");
     while(){
         res = read(fifo_fd, &info, sizeof(CLIENTINFO));
         if(res != ){
             printf("Client arrived!!\n");
             sprintf(buffer, "The result is %d", calc(&info));
             fd1 = open(info.myfifo, O_WRONLY | O_NONBLOCK);
             write (fd1, buffer, strlen(buffer) + );
             close(fd1);
         }

     }
     return ;
 }

OK！

./server.c &

./client 3 + 5

　　看输出吧！