MSVC -Wall 标准标题中的数千条警告是怎么回事?
有些人似乎建议您使用 -Wall，但是当我在一个只有 main.cpp 和一些包含的小型测试项目中这样做时，我收到了 5800 条警告，其中大部分在标准标题或 Windows 标题中.
Some people seem to advise you use -Wall, but when I did it on a small test project which just has a main.cpp with some includes, I get 5800 warnings most of them in standard headers or in windows headers.
这是预期的行为吗?如何让我的编译警告免费?
Is that intended behaviour? How do I go about making my compilation warning free?
这里只是一些阅读乐趣:
Here are just a few for some reading fun:
1>c:program filesmicrosoft visual studio 10.0vcincludestdint.h(105): warning C4668: '_INTPTR' is not defined as a preprocessor macro, replacing with '0' for '#if/#elif'
1>c:program filesmicrosoft visual studio 10.0vcincludewchar.h(109): warning C4820: '_wfinddata64i32_t' : '4' bytes padding added after data member '_wfinddata64i32_t::attrib'
1>c:program filesmicrosoft visual studio 10.0vcincludewchar.h(114): warning C4820: '_wfinddata64i32_t' : '4' bytes padding added after data member '_wfinddata64i32_t::name'
1>c:program filesmicrosoft visual studio 10.0vcincludewchar.h(118): warning C4820: '_wfinddata64_t' : '4' bytes padding added after data member '_wfinddata64_t::attrib'
1>c:program filesmicrosoft visual studio 10.0vcincludewchar.h(488): warning C4820: '_stat32' : '2' bytes padding added after data member '_stat32::st_gid'
1>c:program filesmicrosoft visual studio 10.0vcincludewchar.h(504): warning C4820: 'stat' : '2' bytes padding added after data member 'stat::st_gid'
1>c:program filesmicrosoft visual studio 10.0vcincludewchar.h(520): warning C4820: '_stat32i64' : '2' bytes padding added after data member '_stat32i64::st_gid'
1>c:program filesmicrosoft visual studio 10.0vcincludewchar.h(521): warning C4820: '_stat32i64' : '4' bytes padding added after data member '_stat32i64::st_rdev'
1>c:program filesmicrosoft visual studio 10.0vcincludewchar.h(525): warning C4820: '_stat32i64' : '4' bytes padding added after data member '_stat32i64::st_ctime'
1>c:program filesmicrosoft visual studio 10.0vcincludewchar.h(534): warning C4820: '_stat64i32' : '2' bytes padding added after data member '_stat64i32::st_gid'
1>c:program filesmicrosoft visual studio 10.0vcincludewchar.h(548): warning C4820: '_stat64' : '2' bytes padding added after data member '_stat64::st_gid'
1>c:program filesmicrosoft visual studio 10.0vcincludewchar.h(549): warning C4820: '_stat64' : '4' bytes padding added after data member '_stat64::st_rdev'
1>c:program filesmicrosoft visual studio 10.0vcincludecrtdbg.h(1078): warning C4986: 'operator new[]': exception specification does not match previous declaration
1> c:program filesmicrosoft visual studio 10.0vcinclude
ew(79) : see declaration of 'operator new[]'
1>c:program filesmicrosoft visual studio 10.0vcincludecrtdbg.h(1095): warning C4986: 'operator delete[]': exception specification does not match previous declaration
1> c:program filesmicrosoft visual studio 10.0vcinclude
ew(77) : see declaration of 'operator delete[]'
1>c:program filesmicrosoft visual studio 10.0vcinclude ypeinfo(76): warning C4820: 'type_info' : '3' bytes padding added after data member 'type_info::_M_d_name'
1>c:program filesmicrosoft sdkswindowsv7.0aincludeasetsd.h(114): warning C4668: '__midl' is not defined as a preprocessor macro, replacing with '0' for '#if/#elif'
1>c:program filesmicrosoft sdkswindowsv7.0aincludewinnt.h(8154): warning C4820: '_SECURITY_QUALITY_OF_SERVICE' : '2' bytes padding added after data member '_SECURITY_QUALITY_OF_SERVICE::EffectiveOnly'
1>c:program filesmicrosoft sdkswindowsv7.0aincludewinnt.h(8165): warning C4820: '_SE_IMPERSONATION_STATE' : '2' bytes padding added after data member '_SE_IMPERSONATION_STATE::EffectiveOnly'
1>c:program filesmicrosoft sdkswindowsv7.0aincludewinnt.h(8334): warning C4820: '_QUOTA_LIMITS' : '4' bytes padding added after data member '_QUOTA_LIMITS::PagefileLimit'
1>c:program filesmicrosoft sdkswindowsv7.0aincludewinnt.h(8357): warning C4820: '_QUOTA_LIMITS_EX' : '4' bytes padding added after data member '_QUOTA_LIMITS_EX::PagefileLimit'
1>c:program filesmicrosoft sdkswindowsv7.0aincludewinnt.h(8405): warning C4820: '_JOBOBJECT_BASIC_LIMIT_INFORMATION' : '4' bytes padding added after data member '_JOBOBJECT_BASIC_LIMIT_INFORMATION::SchedulingClass'
1>c:program filesmicrosoft sdkswindowsv7.0aincludewinnt.h(8984): warning C4820: '_FILE_NOTIFY_INFORMATION' : '2' bytes padding added after data member '_FILE_NOTIFY_INFORMATION::FileName'
1>c:program filesmicrosoft sdkswindowsv7.0aincludewinnt.h(9012): warning C4820: '_REPARSE_GUID_DATA_BUFFER' : '3' bytes padding added after data member '_REPARSE_GUID_DATA_BUFFER::GenericReparseBuffer'
1>c:program filesmicrosoft sdkswindowsv7.0aincludewinnt.h(10131): warning C4820: '<unnamed-tag>' : '3' bytes padding added after data member '<unnamed-tag>::Data'
1>c:program filesmicrosoft sdkswindowsv7.0aincludewinnt.h(10241): warning C4820: '<unnamed-tag>' : '4' bytes padding added after data member '<unnamed-tag>::DecreaseTime'
1>c:program filesmicrosoft sdkswindowsv7.0aincludewinnt.h(10262): warning C4820: '<unnamed-tag>' : '4' bytes padding added after data member '<unnamed-tag>::TimerInterval'
1>c:program filesmicrosoft sdkswindowsv7.0aincludewincrypt.h(1440): warning C4668: 'NTDDI_WINLH' is not defined as a preprocessor macro, replacing with '0' for '#if/
推荐答案
Visual C++ /Wall 启用所有在 /W4 处默认禁用的警告.正如您所发现的，默认情况下禁用许多这些警告是有充分理由的(感谢编译器告诉我您添加了填充；我真的很感激！).最好在 Visual C++ 上使用 /W4.
The Visual C++ /Wall enables all of the warnings that are disabled by default at /W4. As you've found out, there is a good reason why a lot of those warnings are disabled by default (thanks, compiler, for telling me you've added padding; I really appreciate it!). It's probably best just to use /W4 on Visual C++.
Intel C++ 也是这样(我不知道其他使用 EDG 前端的编译器).如果您将其设置为 /W5，它会发出大量信息性消息.我个人最喜欢的是，如果存储类说明符不在声明的开头，它会警告您(因此，const static int 不行，但 static const int没问题).
Intel C++ is like this too (I don't know about other compilers that utilize the EDG frontend). If you set it at /W5, it spews out tons of informational messages. My personal favorite is that it warns you if the storage class specifier isn't at the beginning of a declaration (so, const static int is no go, but static const int is fine).
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