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我不明白爲什麼只有一個孩子發送數據給家長（只有第一個孩子）.. 當我做睡眠（5）後，通過管道發送數據到父母然後第二個孩子向父母發送相同的素數。父母和2個孩子之間的管道
有人可以幫助我嗎？因爲他們已經開始使用相同的種子
//--------------------------Consts---------------------------------
#define NUM_OF_CHILDS 2
#define N 20
#define WIN 5
struct msg{
\t pid_t _pid;
\t int _prime;
};
//--------------------------Prototypes-----------------------------
bool is_prime(int num);
void terminate(pid_t child_pid[],int fd[2]);
void do_child(int fd[2]);
void print_pair(const int f_arr[],const int s_arr[]);
//--------------------------Main-------------------------------------
int main()
{
\t int f_arr[N] = {0},
\t \t s_arr[N] = {0},
\t \t ind, //running on children fork
\t \t count1 = 0,
\t \t count2 = 0,
\t \t victory1 = 0,
\t \t victory2 = 0,
\t \t min = 0;
\t int fd[2];
\t bool read1 = false,
\t \t read2 = false;
\t srand((unsigned)time(NULL));
\t pid_t child_pid [NUM_OF_CHILDS];//children pid status array
\t struct msg msg1;
\t if (pipe(fd) == -1)//pipe fd
\t {
\t \t perror("cannot open pipe");
\t \t exit(EXIT_FAILURE);
\t }
\t for(ind = 0; ind < NUM_OF_CHILDS; ind++)
\t {
\t \t child_pid[ind] = fork();// duplicate the current process
\t \t if (child_pid[ind] < 0)//fork failed
\t \t {
\t \t \t perror("Cannot fork()");
\t \t \t exit(EXIT_FAILURE);
\t \t }
\t \t if(child_pid[ind] == 0)/* child : sends message to parent*/
\t \t \t do_child(fd);
\t }
\t /* parent : receives message from child */
\t close(fd[1]); // close the write-end of the pipe
\t //read data from pipe
\t while(read(fd[0],&msg1,sizeof(struct msg)) > 0)
\t {
\t \t if(child_pid[0] == msg1._pid)
\t \t {
\t \t \t f_arr[count1++] = msg1._prime;
\t \t \t read1 = true;
\t \t }
\t \t else
\t \t {
\t \t \t s_arr[count2++] = msg1._prime;
\t \t \t read2 = true;
\t \t }
\t \t if(read1 && read2)
\t \t {
\t \t \t if(f_arr[min] > s_arr[min])
\t \t \t \t victory1++;
\t \t \t else if(f_arr[min] < s_arr[min])
\t \t \t \t victory2++;
\t \t \t read1 = false;
\t \t \t read2 = false;
\t \t \t min++;
\t \t }
\t \t if(victory1 == WIN || victory2 == WIN)
\t \t \t terminate(child_pid,fd);
\t }
\t close(fd[0]);// close the read-end of the pipe
\t print_pair(f_arr,s_arr);
\t return EXIT_SUCCESS ;
}
//---------------------------------------------------------------------
//checking if number is a prime number or not
//and return true or false
bool is_prime(int num)
{
\t int i;
\t if(num==0 || num==1 || num==2)
\t \t return false;
\t for(i=2;i<=num/2;i++)
\t {
\t \t //the number is not prime
\t \t if(num%i == 0)
\t \t \t return false;
\t }
\t //the number is prime
\t return true;
}
//----------------------------------------------------------------
void do_child(int fd[2])
{
\t struct msg message;
\t int num;
\t close(fd[0]);
\t while (1)
\t {
\t \t num = rand() % 1000;
\t \t if(is_prime(num))
\t \t {
\t \t \t message._prime = num;
\t \t \t message._pid = getpid();
\t \t \t write(fd[1], &message, sizeof(struct msg));
\t \t }
\t }
}
//----------------------------------------------------------------
void terminate(pid_t child_pid[],int fd[2])
{
\t int ind,
\t loop;
\t for(ind = 0; ind < NUM_OF_CHILDS; ind++)
\t {
\t \t close(fd[1]);
\t \t //first to give the process an opportunity to die gratefully before
\t \t //using SIGKILL
\t \t kill(child_pid[ind], SIGTERM);
\t \t bool died = false;
\t \t //It will give the process 5 seconds to die gracefully
\t \t for (loop = 0; loop < 5 && !died; ++loop)
\t \t {
\t \t \t int pid;
\t \t \t //the time the child process takes to close down gracefully.
\t \t \t sleep(1);
\t \t \t //to get the return status of that process and prevent zombie processes.
\t \t \t if (waitpid(child_pid[ind], &pid, WNOHANG) == child_pid[ind])
\t \t \t \t died = true;
\t \t }
\t \t //if SIGTERM did not killed the child do SIGKILL
\t \t if (!died)
\t \t {
\t \t \t int pid;
\t \t \t kill(child_pid[ind], SIGKILL);
\t \t \t waitpid(child_pid[ind], &pid, 0);// harvest the zombie
\t \t }
\t }
}
//------------------------------------------------------------------
void print_pair(const int f_arr[],const int s_arr[])
{
\t int ind;
\t for(ind = 0; ind < N; ind++)
\t {
\t \t if(f_arr[ind] == 0 && s_arr[ind] == 0)
\t \t \t break;
\t \t printf("(%d,%d)\n",f_arr[ind],s_arr[ind]);
\t }
}
「但我有一種感覺，你故意避免這種情況」 - 你是對的。 Tnx爲您的評論！ –
我不能得到它的工作:( –