用FIFO编写的进程之间通信的程序，可是有错误，请高手指教 - Chinaunix

#include<stdio.h>;
#include<stdlib.h>;
#include<fcntl.h>;
#include<sys/types.h>;
#include<sys/stat.h>;
#include<limits.h>;
#include<unistd.h>;
#include"err_exit.h"
#define FIFO_FILE "myfifo"
static pid_t child_id[1];
static int myfifo1(void);
static int myfifo2(void);
static int fifo_fd,n;
static char buffer[BUFSIZ+1];
static char some_data[]="hello,world!";
void sig_usr(int signo)/*信号SIGUSR1的句柄*/
{
printf("received SIGUSR1 \n");
/*创建新的子进程2*/
child_id[1]=fork();
if(child_id[1]==0)
{
/*自己定义的进程通信函数*/
myfifo1();
myfifo2();
/*子进程2的功能*/
child_function2();
exit(0);
}
else if(child_id[1]<0)
printf("fork error.");
}
/*子进程执行此函数*/
int child_function1()
{
printf("this is child1:\n");
printf("done1.\n");
/*发出信号通知父进程子进程1已完成*/
kill(getppid(),SIGUSR1);
exit(EXIT_SUCCESS);
return 0;
}
int child_function2()
{
printf("this is child2:\n");
printf("Done2.\n");
exit(EXIT_SUCCESS);
return 0;
}
int main(int argc, char *argv[])
{
int i;
int status;
struct sigaction usr_action;
sigset_t block_mask;
/*初始化信号句柄*/
sigfillset(&block_mask);
usr_action.sa_handler=sig_usr;/*指定与信号相关连的动作*/
usr_action.sa_mask=block_mask;
usr_action.sa_flags=0;
/*为信号SIGUSR1*/
sigaction(SIGUSR1,&usr_action,NULL);
/*创建子进程1*/
child_id[0]=fork();
if(child_id[0]==0)
{ child_function1();
exit(0); }
else if(child_id[0]<0)
printf("fork error.");
/*父进程*/
for(i=0;i<2;i++)
waitpid(child_id[i],&status,0);
printf("data sending is over.\n");
exit(EXIT_SUCCESS);
}
int myfifo2(void)
{
if(access(FIFO_FILE,F_OK)==-1)
{ if(mkfifo(FIFO_FILE,0666)!=0)
{
printf("could not create fifo %s\n",FIFO_FILE);
exit(EXIT_FAILURE);
}
}
if((fifo_fd=open(FIFO_FILE,O_RDONLY))<0)
{
printf("could not open fifo %s\n",FIFO_FILE);
exit(EXIT_FAILURE);
}
printf("child2 %d opened:%s\n",getpid(),FIFO_FILE);
while((n=read(fifo_fd,buffer,BUFSIZ))>;0)
printf("child2 %d received %d bytes:%s\n",getpid(),n,buffer);
close(fifo_fd);
printf("child2 %d received %d bytes then finished\n",getpid(),n);
return 0;
}
int myfifo1(void)
{
int fifo_fd,n;
char buffer[BUFSIZ+1];
char some_data[]="hello,world!";
if((fifo_fd=open(FIFO_FILE,O_WRONLY))<0)
{
printf("could not open fifo %s\n",FIFO_FILE);
exit(EXIT_FAILURE);
}
printf("child1 %d opened:%s\n",getpid(),FIFO_FILE);
if(n=write(fifo_fd,some_data,strlen(some_data))==-1)
err_exit("FIFO broken");
printf("child1 %d write %d bytes\n",getpid(),n);
close(fifo_fd);
printf("child1 %d write %d bytes then finished\n",getpid(),n);
return 0;
}

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