Callback 函数

sybaselu

1. 
   
2. #include <stdio.h>
   
3. 
   
4. typedef void (*pDesc)(void);
   
5. typedef void (*pFee)(long);
   
6. 
   
7. void Desc()
   
8. {
   
9.     printf("Address: %s\n", "I come from BTW");
   
10. }
    
11. 
    
12. void Fee(long pLong)
    
13. {
    
14.     printf("Fee: %ld\n",pLong);
    
15. }
    
16. 
    
17. void Dothing(char* pName, pDesc, pFee, int pScore)
    
18. {
    
19.     printf("%s\n", pName);
    
20.     pDesc();
    
21.     pFee(100);
    
22.     printf("%d\n", pScore);
    
23. }
    
24. 
    
25. int main()
    
26. {
    
27.     pDesc pDescstu1;
    
28.     pFee  pFeestu1;
    
29.     pDescstu1 = Desc;
    
30.     pFeestu1 = Fee;
    
31. 
    
32.      Dothing("Ascort", pDescstu1, pFeestu1, 60);
    
33. 
    
34.     return 0;
    
35. }
    
36. [root@root Stuff]# ./a.out
    
37. Ascort
    
38. 60
    
39. [root@root Stuff]#
    

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回调函数没有打印呢？ 在sqlite3_exec()中的回调函数的参数在sqlite3_exec()的实现中给出的。

windwiny

这是什么方法 ?  .. 函数定义中第 二,三 个参数留空? ..把类型名当参数使用??..

牛X



回这个帖是第5次修改了,, 而且程序也能通过编译运行 不崩溃.....

DoDo

2. #include <stdio.h>
4. typedef void (*pDesc)(void);
5. typedef void (*pFee)(long);
7. void Desc()
8. {
9.         printf("Address: %s\n", "I come from BTW");
10. }
12. void Fee(long pLong)
13. {
14.         printf("Fee: %ld\n",pLong);
15. }
17. void Dothing(char* pName, pDesc desc, pFee fee, int pScore)
18. {
19.         printf("%s\n", pName);
20.         desc();
21.         fee(100);
22.         printf("%d\n", pScore);
23. }
25. int main()
26. {
27.         pDesc pDescstu1;
28.         pFee  pFeestu1;
29.         pDescstu1 = Desc;
30.         pFeestu1 = Fee;
32.         Dothing("Ascort", Desc, Fee, 60);
34.         return 0;
35. }

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1. rf@RemoteFish:/dev/shm$ gcc a.c
2. rf@RemoteFish:/dev/shm$ ./a.out
3. Ascort
4. Address: I come from BTW
5. Fee: 100
6. 60

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sybaselu

It suddently to reminder  me that  the prototype of the third parameter in  the sqlite3_exec(...) be defined like below:

1. 
   
2. typedef int (*sqlite3_callback)(int*, char**, char**)
   

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then the prototype of the sqlite3_exec() be defined like below:

1. 
   
2. int sqlite3_exec(sqlite3**, sqlite3_callback, char*, char** zErrMsg)
   

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however, the implementation of sqlite3_exec() be implemented likes this

1. 
   
2. int sqlite3_exec(sqlite3** _db, sqlite3_callback xCallback, char* , char** zErrMsg)
   
3. {
   
4.    xCallback(...)
   

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Tks, your simple but very useful help told me that what does a good man shoud be likes