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我已經編寫了這個代碼，它在2個不同的程序（存在於同一個文件夾中）中具有2個不同的進程，該程序在單個命名管道上運行。 第一個程序有一個連續通過列表的指針。當從另一個程序（timer.c）收到'定時器中斷'時，指針必須停止，並刪除特定的列表。在兩個進程之間使用命名管道連續通信
這是我的代碼：
ball.c
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <limits.h>
#include <string.h>
#include <unistd.h>
#define FIFO_NAME "my_fifo" /* the fifo name */
#define BUFFER_SIZE 10
struct node
{
int data;
struct node* next;
};
struct node* create_new()
{
struct node* temp = (struct node *)malloc(sizeof(struct node)*1);
return temp;
};
void populate_list(struct node **head, int players)
{
struct node *current, *temp;
int i = 1;
temp = create_new();
temp->data = i++;
temp->next = temp;
*head = temp;
while(i <= players){
current = create_new();
current->data = i;
current->next = *head;
temp->next = current;
temp = current;
i++;
}
}
void display_list(struct node **head)
{
if(NULL == *head)
{
printf("the list is empty\n");
}
else
{
struct node *temp = *head;
while(temp->next != *head){
printf("%d - ", temp->data);
temp = temp->next;
}
printf("%d\n", temp->data);
}
}
void delete_player(struct node **pos)
{
printf("Deleting Player - '%d'\n", (*pos)->data);
struct node *temp, *ptr;
temp = ptr = *pos;
while(temp->next != *pos){
temp = temp->next;
}
temp->next = ptr->next;
free(ptr);
*pos = temp;
}
int main(int argc, char **argv)
{
int res;
char buffer[BUFFER_SIZE + 1];
if (access(FIFO_NAME, F_OK) == -1) /* check if fifo already exists*/
{
res = mkfifo(FIFO_NAME, 0777); /* if not then, create the fifo*/
if (res != 0) {
fprintf(stderr, "Could not create fifo %s\n", FIFO_NAME);
exit(EXIT_FAILURE);
}
}
memset(buffer, '\0', BUFFER_SIZE+1); /* clear the string */
printf("Process %d - opening FIFO\n\n", getpid());
res = open(FIFO_NAME, O_RDWR | O_NONBLOCK);
struct node *head = NULL;
int players;
printf("Enter the number of players: ");
scanf("%d", &players);
populate_list(&head, players);
printf("\nThe players are: \n");
display_list(&head);
printf("\n-------------------Game Started-----------------\n");
struct node *pos, *start = head;
int breakflag = 0;
while(start->next != start)
{
while(breakflag == 0)
{
read(res, buffer, BUFFER_SIZE+1);
if(strcmp(buffer, "intr") == 0){
breakflag = 1;
memset(buffer, '\0', BUFFER_SIZE+1);
}
start = start->next;
}
pos = start;
start = start->next;
printf("\nThe ball is currently with Player '%d'\n", pos->data);
delete_player(&pos);
display_list(&pos);
breakflag = 0; //Restart the passing game
}
printf("\nWinner: Player '%d'\n", start->data);
free(start);
write(res, "stop", strlen("stop")+1);
if(res != -1)
(void)close(res); /* close the fifo */
printf("Process %d - ballpass.c - finished\n", getpid());
return 0;
}
/timer.c裏
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <limits.h>
#define FIFO_NAME "my_fifo" /* the fifo name */
#define FIFO_NAME1 "my_fifo1" /* the fifo name */
#define BUFFER_SIZE 10
/* Used to generate the timer delay */
void waitFor(unsigned int secs)
{
unsigned int retTime = time(0) + secs;
while(time(0) < retTime);
}
int main()
{
int res, i, random_time;
char buffer[BUFFER_SIZE + 1];
if (access(FIFO_NAME, F_OK) == -1) { /* check if fifo already exists*/
res = mkfifo(FIFO_NAME, 0777); /* if not then, create the fifo*/
if (res != 0) {
fprintf(stderr, "Could not create fifo %s\n", FIFO_NAME);
exit(EXIT_FAILURE);
}
}
memset(buffer, '\0', BUFFER_SIZE+1); /* clear the string */
printf("Process %d - opening FIFO\n\n", getpid());
res = open(FIFO_NAME, O_RDWR | O_NONBLOCK);
while(1)
{
read(res, buffer, BUFFER_SIZE+1);
if(strcmp(buffer, "stop") == 0)
break;
random_time = rand()%10;
waitFor(random_time);
write(res, "intr", strlen("intr")+1);
printf("Process %d - Timer sent interrupt\n");
}
if (res != -1)
(void)close(res); /* close the fifo */
printf("Process %d - timer.c - finished\n", getpid());
exit(EXIT_SUCCESS);
}
問題是我的第一個前衛無法趕上計時器正常。我的定時器程序也從來沒有收到第一個編髮送的「停止」。因此根本沒有同步。 有時，在從定時器收到2個'中斷'之後，第1個prog會捕獲並刪除該節點。
我在這裏錯過了什麼？