今天研究c++ const 的问题,顺便做了一下gcc 与 clang 的代码编译错误提示对比,结论是,clang这个晚辈确实比gcc人性化多了。
参考:
http://www.cnblogs.com/Fancyboy2004/archive/2008/12/23/1360810.html
以下是测试代码:
#include <cstdlib> class Apple { public: Apple (){}; /* constructor */ int GetCount() /* 非const 成员函数 */ { return m_iData; }; protected: int m_iData; }; /* ----- end of class Apple ----- */ using namespace std; int main ( int argc, char *argv[] ) { const Apple apple; apple.GetCount(); /* 错误 */ return EXIT_SUCCESS; } // ---------- end of function main ---------- //save to a.cc
gcc编译命令:
$ g++ a.cc a.cc: In function ‘int main(int, char**)’: a.cc:22: error: passing ‘const Apple’ as ‘this’ argument of ‘int Apple::GetCount()’ discards qualifiers
clang:
$ clang++ a.cc a.cc:22:5: error: member function 'GetCount' not viable: 'this' argument has type 'const Apple', but function is not marked const apple.GetCount(); /* 错误 */ ^~~~~ a.cc:8:13: note: 'GetCount' declared here int GetCount() /* 非const 成员函数 */ ^ 1 error generated.