Question

我需要确保在发生隐式转换时，编译器应该抛出警告/错误，如下面的代码所示：

int32_t y = 9;
uint32_t x = y;
y = -1;
x = y;

在gcc中我可以一起使用 -Wconversion -Wsign-conversion 编译器标志来报告这样的问题 - VC ++构建是否有类似的选项？

Answer 1

请参阅Compiler Warnings That Are Off by Default

C4287（第3级）'运算符'：无符号/负常数不匹配
C4365（第4级）'操作'：从'type_1'转换为'type_2'，签名/未签名不匹配
C4388（第4级）签名/未签名不匹配
C4287（第3级）'运算符'：无符号/负常数不匹配

还有其他与截断有关。

一般情况下，您可以使用/Wall打开所有警告，然后根据您的代码构建抑制列表，因为其中很多都是非常嘈杂的。

例如，在DirectX Tool Kit for DX11中，我使用/Wall以及pch.h中的以下抑制：

// VS 2013 related Off by default warnings
#pragma warning(disable : 4619 4616 4350 4351 4472 4640 5038)
// C4619/4616 #pragma warning warnings
// C4350 behavior change
// C4351 behavior change; warning removed in later versions
// C4472 'X' is a native enum: add an access specifier (private/public) to declare a WinRT enum
// C4640 construction of local static object is not thread-safe
// C5038 can't use strictly correct initialization order due to Dev12 initialization limitations

// Off by default warnings
#pragma warning(disable : 4061 4265 4365 4571 4623 4625 4626 4628 4668 4710 4711 4746 4774 4820 4987 5026 5027 5031 5032 5039)
// C4061 enumerator 'X' in switch of enum 'X' is not explicitly handled by a case label
// C4265 class has virtual functions, but destructor is not virtual
// C4365 signed/unsigned mismatch
// C4571 behavior change
// C4623 default constructor was implicitly defined as deleted
// C4625 copy constructor was implicitly defined as deleted
// C4626 assignment operator was implicitly defined as deleted
// C4628 digraphs not supported
// C4668 not defined as a preprocessor macro
// C4710 function not inlined
// C4711 selected for automatic inline expansion
// C4746 volatile access of '<expression>' is subject to /volatile:<iso|ms> setting
// C4774 format string expected in argument 3 is not a string literal
// C4820 padding added after data member
// C4987 nonstandard extension used
// C5026 move constructor was implicitly defined as deleted
// C5027 move assignment operator was implicitly defined as deleted
// C5031/5032 push/pop mismatches in windows headers
// C5039 pointer or reference to potentially throwing function passed to extern C function under - EHc

// Windows 8.1 SDK related Off by default warnings
#pragma warning(disable : 4471 4917 4986 5029)
// C4471 forward declaration of an unscoped enumeration must have an underlying type
// C4917 a GUID can only be associated with a class, interface or namespace
// C4986 exception specification does not match previous declaration
// C5029 nonstandard extension used

它确实需要维护成本以跟上编译器随时间的变化，这也是为什么我有评论来提醒我每个人的用途。

Visual C ++编译器选项

1 个答案: