關於printf打印不出來問題

時間 2019-11-20

標籤關於 printf 打印出來問題简体版

原文原文鏈接

1#include<unistd.h>
2 #include <sys/types.h>
3 #include <stdio.h>
4 #include <sys/ipc.h>
5 #include <sys/shm.h>
6 #include <stdlib.h>
7 #include <string.h>
8 int main()
9 {
10     int shmid;
11     pid_t ret_fork;
12     shmid = shmget(0,1024,IPC_CREAT|0600);
13     if(shmid == -1)
14     {
15         printf("build shm error\n");
16         return -1;
17     }
18     ret_fork = fork();
19     if(ret_fork<0)
20     {
21         printf("error\n");
22         exit(0);
23     }
24     else if(ret_fork == 0)
25     {
26         char *son_p;
27         son_p = (char *)shmat(shmid,NULL,0);緩存

27         son_p = (char *)shmat(shmid,NULL,0);
28         while(1)
29         {
30             printf("son:");
31             fflush(stdout);
32             gets(son_p);
33             if(strncmp(son_p,"byebye",6)==0)
34             {
35                 shmdt(son_p);
36                 exit(0);
37             }
38
39         }
40     }
41     else if(ret_fork > 0)
42     {
43         char *father_p;
44         father_p = (char *)shmat(shmid,NULL,0);
45         while(1)
46         {
47             if(*father_p !='\0')
48             {
49                 printf("from son:%s",father_p);
50                 if(strncmp(father_p,"byebye",6)==0)
51                 {
52                     wait(NULL);   函數

53                     shmdt(father_p);
54                     shmctl(shmid,IPC_RMID,NULL);
55                 }
56                 memset(father_p,0,1024);
57             }
58             usleep(10);
59         }
60     }
61
62 } ui

27         son_p = (char *)shmat(shmid,NULL,0);
28         while(1)
29         {
30             printf("son:");
31             fflush(stdout);
32             gets(son_p);
33             if(strncmp(son_p,"byebye",6)==0)
34             {
35                 shmdt(son_p);
36                 exit(0);
37             }
38
39         }
40     }
41     else if(ret_fork > 0)
42     {
43         char *father_p;
44         father_p = (char *)shmat(shmid,NULL,0);
45         while(1)
46         {
47             if(*father_p !='\0')
48             {
49                 printf("from son:%s\n",father_p);
50                 if(strncmp(father_p,"byebye",6)==0)
51                 {
52                     wait(NULL);   進程

53                     shmdt(father_p);
54                     shmctl(shmid,IPC_RMID,NULL);
55                 }
56                 memset(father_p,0,1024);
57             }
58             usleep(10);
59         }
60     }
61
62 } ip