用宏处理函数调用或系统调用错误检测

ec.h

 1 #include "/usr/include/stdint.h"    //intptr_t的声明
 2 
 3 #define EC_CLEANUP_BGN
 4     ec_cleanup_bgn:
 5     {    
 6     
 7 #define EC_CLEANUP_END
 8     }
 9     
10 
11 //注意__FILE__等是两个下划线
12 #define ec_cmp(var, target)
13     {
14         if((intptr_t)(var) == (intptr_t)(target))
15         {
16             std::cout << __func__ << "[" << __FILE__ << ":" << __LINE__ << "]
";
17             goto ec_cleanup_bgn;
18         }
19     }
20 
21 #define ec_null(x) ec_cmp(x, NULL)
22 #define ec_neg1(x) ec_cmp(x, -1)
23 #define ec_false(x) ec_cmp(x, false)

main.c

 1 #include "ec.h"
 2 
 3 #include <fcntl.h>
 4 #include <unistd.h>
 5 
 6 #include <iostream>
 7 #include <cstdlib>
 8 #include <cstdio>
 9 
10 using std::cout;
11 using std::endl;
12 
13 bool fcn();
14 
15 int main(void)
16 {
17     ec_false(fcn());
18     
19     //exit(EXIT_SUCCESS);
20     cout << "EXIT_SUCCESS
";
21     return 0;
22     
23 EC_CLEANUP_BGN
24     //exit(EXIT_FAILURE);
25     cout << "EXIT_FAILURE
";
26     return -1;
27 EC_CLEANUP_END
28 
29 }
30 
31 bool fcn()
32 {
33     char* p = NULL;
34     int fdin = -1, fdout = -1;
35     
36     ec_null(p = (char*)malloc(1000));
37     ec_neg1(fdin = open("in", O_RDONLY));
38     ec_neg1(fdout = open("out", O_WRONLY));
39     
40     return true;
41     
42 EC_CLEANUP_BGN
43     free(p);
44     if(fdin != -1)
45         (void)close(fdin);
46     if(fdout != -1)
47         (void)close(fdout);
48     return false;
49 EC_CLEANUP_END
50 
51 }

记住这种用宏的方式处理函数调用或者系统调用错误检测的实现，虽然这个例子不完善，有BUG。