windows 是否可以检查您是否正在使用 Microsoft C 编译器为 64 位构建？
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Is it possible to check whether you are building for 64-bit with Microsoft C Compiler?
提问by dreamlax
Is there a simple preprocessor macro that is defined for a 64-bit build? I thought _WIN64might have been it, but even when I build a 32-bit target, the parts enclosed in a #ifdef _WIN64 ... #endifare compiled in, and this is causing problems. It's Friday and I can't think straight, but I'm sure I'm overlooking something very simple here. Maybe even something involving sizeof.
是否有为 64 位构建定义的简单预处理器宏？我想_WIN64可能是这样，但即使我构建了一个 32 位目标，包含在 a#ifdef _WIN64 ... #endif中的部分也会被编译，这会导致问题。今天是星期五，我无法直接思考，但我确定我在这里忽略了一些非常简单的事情。甚至可能涉及sizeof.
回答by Bruce Ikin
I have always used _WIN64 to check if it is a 64 bit build.
我一直使用 _WIN64 来检查它是否是 64 位版本。
N.B. _WIN32 is also always (automatically) defined by MSVC in 64 bit builds, so check for _WIN64 before you check for _WIN32:
注意 _WIN32 也总是（自动）由 MSVC 在 64 位版本中定义，因此在检查 _WIN32 之前检查 _WIN64：
#if defined( _WIN64 )
// Windows 64 bit code here
#elif defined( _WIN32 )
// Windows 32 bit code here
#else
// Non-Windows code here
#endif
回答by Michael Burr
It sounds like your problem might be related to a header or project setting improperly defining _WIN64- that should be left to the compiler.
听起来您的问题可能与不正确定义的标头或项目设置有关_WIN64- 这应该留给编译器。
There's a subtle difference between WIN64and _WIN64(at least for the Microsoft compilers - other compilers should follow suit, but not all do):
WIN64和_WIN64( 至少对于 Microsoft 编译器 - 其他编译器应该效仿，但并非所有人都这样做)之间存在细微差别：
_WIN64is defined by the compilerwhen it's building a program for a Windows 64-bit platform. Note that this name is in the compiler implementor's namespace (leading underscore followed by a capital letter)WIN64is defined by the Windows Platform SDK(or whatever they're calling it this year) when targeting a 64-bit platform.
_WIN64由编译器在为 Windows 64 位平台构建程序时定义。请注意，此名称位于编译器实现者的命名空间中（前导下划线后跟大写字母）WIN64当面向 64 位平台时，由Windows 平台 SDK（或他们今年所称的任何名称）定义。
So if you're only including standard headers and don't take other measures to define it, WIN64will notbe defined.
所以如果你只包含标准头，不采取其他措施来定义它，WIN64将不会被定义。
There's a similar story for _WIN32and WIN32- but checking other compilers: GCC 3.4.5 does define WIN32even if only standard headers are used. As does Digital Mars.
有一个类似的故事_WIN32and WIN32- 但检查其他编译器：WIN32即使只使用标准头文件，GCC 3.4.5 也确实定义了。数字火星也是如此。
Microsoft's compilers and Comeau do not.
Microsoft 的编译器和 Comeau 没有。
Another bit of (hopefully) well known trivia is that _WIN32and WIN32are set when targeting 64-bit Windows platforms. Too much stuff would have broken otherwise.
（希望）公知的琐事的另一个位是_WIN32与WIN32靶向的64位的Windows平台时被设置。否则太多东西会坏掉。
回答by Ron Pihlgren
The Visual C++ compiler defines the following macros:
Visual C++ 编译器定义了以下宏：
- _M_IX86 - x86 platform
- _M_IA64 - ia64 platform
- _M_X64 - x64 platform
- _M_IX86 - x86 平台
- _M_IA64 - ia64 平台
- _M_X64 - x64 平台
回答by dirkgently
Check your project's build properties, particularly the preprocessor section. Are you defining _WIN64somewhere in WIN32builds? The sizeofthing probably won't work since you cannot use in a #iftest.
检查项目的构建属性，尤其是预处理器部分。您是否_WIN64在WIN32构建中定义某个地方？这sizeof东西可能不起作用，因为你不能在#if测试中使用。
