Item 18: Make interfaces easy to use correctly and hard to use incorrectly(Effective C++)

• Good interfaces are easy to use correctly and hard to use incorrectly. Your should strive for these characteristics in all your interfaces.

• Ways to facilitate correct use include consistency in interfaces and behavioral compatibility with built-in types.

• Ways to prevent errors include creating new types, restricting operations on types, constraining object values, and eliminating client resource management responsibilities.

• TR1::shared_ptr supports custom deleters. This prevents the cross-DLL problem, can be used to automatically unlock mutexes (see Item 14), etc.

 1 #include <iostream>
 2 #include <string>
 3 #include <boost/shared_ptr.hpp>
 4 #include <fstream>
 5 using namespace std;
 6 
 7 class Test
 8 {
 9 public:
10     void test(Test* t)
11     {
12         ofstream out("1.txt");
13         out << "test in class" << endl;
14         out.close();
15     }
16 };
17 
18 void test(Test* t)
19 {
20     ofstream out("1.txt");
21     out << "test in global" << endl;
22     out.close();
23 }
24 
25 void a()
26 {
27     Test* t = new Test();
28     //void (Test::*funcPtr)(Test*) = &Test::test;
29     boost::shared_ptr<Test> sp(t, test);    
30 }
31 
32 int main()
33 {
34     a();
35     
36     cin.get();
37     return 0;
38 }