g++；警告：将永远不会执行 继承了C++项目。我通过一个生成文件在RHEL5.5中构建GCC4.1.2。该项目是巨大的（数百个文件），一般来说，代码是相当不错的。然而，在编译过程中，我经常会收到一条GCC警告，上面说： /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/allocator.h: In constructor ‘std::allocator<_Alloc>::allocator() [with _Tp = char]’: /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/allocator.h:97: warning: will never be executed /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/allocator.h:97: warning: will never be executed /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/ext/new_allocator.h: In constructor ‘__gnu_cxx::new_allocator<_Tp>::new_allocator() [with _Tp = char]’: /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/ext/new_allocator.h:65: warning: will never be executed /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/allocator.h: In destructor ‘std::allocator<_Alloc>::~allocator() [with _Tp = char]’: /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/allocator.h:105: warning: will never be executed /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/ext/new_allocator.h: In destructor ‘__gnu_cxx::new_allocator<_Tp>::~new_allocator() [with _Tp = char]’: /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/ext/new_allocator.h:72: warning: will never be executed /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/allocator.h: In copy constructor ‘std::allocator<_Alloc>::allocator(const std::allocator<_Alloc>&) [with _Tp = char]’: /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/allocator.h:100: warning: will never be executed /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/allocator.h:99: warning: will never be executed /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/ext/new_allocator.h: In copy constructor ‘__gnu_cxx::new_allocator<_Tp>::new_allocator(const __gnu_cxx::new_allocator<_Tp>&) [with _Tp = char]’: /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/ext/new_allocator.h:67: warning: will never be executed /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/allocator.h: In destructor ‘std::allocator<_Alloc>::~allocator() [with _Tp = char]’: /usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/allocator.h:105: warning: will never be executed /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../../../include/c++/4.1.2/bits/allocator.h:在构造函数“std:：allocator:：allocator（）[with _Tp=char]”中： /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../include/c++/4.1.2/bits/allocator.h:97:警告：永远不会执行 /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../include/c++/4.1.2/bits/allocator.h:97:警告：永远不会执行 /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../../include/c++/4.1.2/ext/new\u allocator.h:在构造函数“\uu gnu\u cxx:：new\u allocator:：new\u allocator（）[带_Tp=char]”中： /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../include/c++/4.1.2/ext/new_分配器。h:65:警告：永远不会执行 /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../include/c++/4.1.2/bits/allocator.h:在析构函数“std:：allocator:：~allocator（）[with _Tp=char]”中： /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../../include/c++/4.1.2/bits/allocator.h:105:警告：永远不会执行 /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../../include/c++/4.1.2/ext/new\u allocator.h:在析构函数中“\uu gnu\u cxx:：new\u allocator:：~new\u allocator（）[带\u Tp=char]： /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../include/c++/4.1.2/ext/new_allocator.h:72:警告：永远不会执行 /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../../../include/c++/4.1.2/bits/allocator.h:在复制构造函数“std:：allocator:：allocator（const std:：allocator&）[with _Tp=char]”中： /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../../include/c++/4.1.2/bits/allocator.h:100:警告：永远不会执行 /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../../include/c++/4.1.2/bits/allocator.h:99:警告：永远不会执行 /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../include/c++/4.1.2/ext/new\u allocator.h：在复制构造函数中“\u gnu\u cxx:：new\u allocator:：new\u allocator（const\u gnu\u cxx:：new\u allocator&”）[带\u Tp=char]： /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../include/c++/4.1.2/ext/new_allocator.h:67:警告：永远不会执行 /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../include/c++/4.1.2/bits/allocator.h:在析构函数“std:：allocator:：~allocator（）[with _Tp=char]”中： /usr/lib/gcc/i386 redhat linux/4.1.2/../../../../../../../../../include/c++/4.1.2/bits/allocator.h:105:警告：永远不会执行

它没有给我错误产生的源文件或行号。我要冒险说GCC的标题很好，所以这里发生了什么？我以前从未遇到过这种特殊的警告。

根据位于的gcc bug 46158，

-Wunreachable code

一直被破坏，并从

gcc-4.5

起被删除。很可能你的问题实际上不是问题。（我个人认为，除非有特殊的理由使用<代码> 4.1.2 ，否则它将是一个较新的GCC／G+ +，它已经将近6年了。

< P>这个bug报告在底部

-Wunreachable代码已损坏，已从GCC 4.5中删除。不要使用它

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因此，忽略警告听起来并不是一个完全糟糕的主意。

非主题：谷歌搜索“警告：永远不会执行”\uu gnu\u cxx:：new\u allocator”返回此页面作为第二个结果。头asplode@Bribles第一个结果返回一个“-Wunreachable代码已被破坏并已从GCC 4.5中删除”。建议从CXXFLAGS中删除此警告选项。@harpun您的google fu很强大！实际上，我并没有把二和二放在一起，并意识到错误是由CXXFLAG选项造成的。升级gcc在列表中。我认为使用已知的工作配置设置项目环境是一个很好的第一步。不过，我很想看看我在gcc升级中遇到了哪些“有趣”的问题。