pthread 学习系列 case1

 1 #include <stdio.h>
 2 #include <unistd.h>
 3 #include <stdlib.h>
 4 #include <pthread.h>
 5 
 6 
 7 void *thread_foo_func(void *);
 8 void *thread_bar_func(void *);
 9 
10 
11 int global = 4;
12 
13 
14 int main(){
15   int local = 8;
16   int foo, bar;
17   pthread_t fthread, bthread;
18   foo = pthread_create(&fthread, NULL, thread_foo_func, (void *)&local);
19   bar = pthread_create(&bthread, NULL, thread_bar_func, (void *)&local);
20   if (foo != 0 || bar != 0){
21     printf("thread creation failed.\n");
22     return -1;
23   }
24 
25 
26   foo = pthread_join(fthread, NULL);
27   bar = pthread_join(bthread, NULL);
28   if (foo != 0 || bar != 0){
29     printf("thread join failed.\n");
30     return -2; 
31   }
32 
33 
34   printf("In thread main");
35   printf("address of global %d: %x\n", global, &global);
36   printf("address of main local %d: %x\n", local, &local);
37 
38   return 0;
39 }
40 
41 
42 void *thread_foo_func(void *arg){
43   int foo_local = 16;
44   global  ++;
45   *(int *)arg = 10;
46   printf("In thread foo_func");
47   printf("address of global %d: %x\n", global, &global);
48   printf("address of main local %d: %x\n", *(int *)arg, arg);
49   printf("address of foo local: %x\n", &foo_local);
50   printf("\n");
51 }
52 
53 
54 void *thread_bar_func(void *arg){
55   int bar_local = 32;
56   global  ++;
57   *(int *)arg = 20;
58   printf("In thread bar_func");
59   printf("address of global %d: %x\n", global, &global);
60   printf("address of main local %d: %x\n", *(int *)arg, arg);
61   printf("address of bar local: %x\n", &bar_local);
62   printf("\n");
63 }

In thread foo_funcaddress of global 5: 8049a48
address of main local 10: bfc567b8
address of foo local: b7f553c4

In thread bar_funcaddress of global 6: 8049a48
address of main local 20: bfc567b8
address of bar local: b75543c4

In thread mainaddress of global 6: 8049a48
address of main local 20: bfc567b8

 1 int global = 6;
 2 
 3 int main(int argc,char** argv)
 4 {
 5     int var=10;
 6     int pid=fork();
 7     if(pid==-1){
 8         printf("error!");
 9     }   
10     else if(pid==0){
11         global++;
12         var++;
13         printf("This is the child process!\n");
14     }   
15     else{
16         printf("This is the parent process! child processid=%d\n",pid);
17     }   
18     printf("%d, %d, %d \n", getpid(), global, var); 
19 
20     return 1;                                                                                                                           
21 }

This is the child process!
10769, 7, 11 
This is the parent process! child processid=10769
10768, 6, 10