我的Linux开发项目使用Clang vs GCC

我的Linux开发项目使用Clang vs GCC

编辑：

海湾合作委员会的成员确实改善了海湾合作委员会（啊竞争）的诊断经验。他们创建了一个Wiki页面在此处进行展示。gcc
4.8现在也具有很好的诊断功能（gcc 4.9x添加了颜色支持）。Clang仍然处于领先地位，但差距正在缩小。

---

原版的：

对于学生，我会无条件推荐Clang。

现在尚不清楚在gcc和Clang之间生成代码的性能（尽管我认为gcc 4.7仍然处于领先地位，我还没有最终的基准），但是对于学生来说，学习实际上并不重要。

另一方面，对于初学者来说，Clang极其清晰的诊断无疑更容易理解。

考虑以下简单代码段：

#include <string>#include <iostream>struct Student {std::string surname;std::string givenname;}std::ostream& operator<<(std::ostream& out, Student const& s) {  return out << "{" << s.surname << ", " << s.givenname << "}";}int main() {  Student me = { "Doe", "John" };  std::cout << me << "n";}

您会立即注意到，在定义了

Student

类之后，分号就消失了，对:)吗？

好吧，海湾合作委员会也注意到了：

prog.cpp:9: error: expected initializer before ‘&’ tokenprog.cpp: In function ‘int main()’:prog.cpp:15: error: no match for ‘operator<<’ in ‘std::cout << me’/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/ostream:112: note: candidates are: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>& (*)(std::basic_ostream<_CharT, _Traits>&)) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/ostream:121: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ios<_CharT, _Traits>& (*)(std::basic_ios<_CharT, _Traits>&)) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/ostream:131: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(std::ios_base& (*)(std::ios_base&)) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/ostream:169: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(long int) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/ostream:173: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(long unsigned int) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/ostream:177: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(bool) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/bits/ostream.tcc:97: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(short int) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/ostream:184: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(short unsigned int) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/bits/ostream.tcc:111: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(int) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/ostream:195: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(unsigned int) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/ostream:204: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(long long int) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/ostream:208: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(long long unsigned int) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/ostream:213: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(double) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/ostream:217: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(float) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/ostream:225: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(long double) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/ostream:229: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(const void*) [with _CharT = char, _Traits = std::char_traits<char>]/usr/lib/gcc/i686-pc-linux-gnu/4.3.4/include/g++-v4/bits/ostream.tcc:125: note:      std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_streambuf<_CharT, _Traits>*) [with _CharT = char, _Traits = std::char_traits<char>]

Clang也不是这里的主角，但仍然：

/tmp/webcompile/_25327_1.cc:9:6: error: redefinition of 'ostream' as different kind of symbolstd::ostream& operator<<(std::ostream& out, Student const& s) {     ^In file included from /tmp/webcompile/_25327_1.cc:1:In file included from /usr/include/c++/4.3/string:49:In file included from /usr/include/c++/4.3/bits/localefwd.h:47:/usr/include/c++/4.3/iosfwd:134:33: note: previous definition is here  typedef basic_ostream<char>ostream;        ///< @isiosfwd       ^/tmp/webcompile/_25327_1.cc:9:13: error: expected ';' after top level declaratorstd::ostream& operator<<(std::ostream& out, Student const& s) { ^ ;2 errors generated.

我故意选择一个示例，该示例会触发一个不清楚的错误消息（来自语法上的歧义），而不是典型的“哦，我的上帝Clang读了我的思想”示例。尽管如此，我们注意到Clang避免了大量错误。无需将学生吓跑。