macos 在 OSX 10.6 上为 C++ 应用程序的默认构建定义的 __LP64__ 在哪里？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/6721037/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Where is __LP64__ defined for default builds of C++ applications on OSX 10.6?
提问by Dan Nissenbaum
I am building a 3rd-party library in 32-bit mode on OSX 10.6 (the library is Xerces 2.8). I have determined that the preprocessor definition __LP64__is set. However, as far as I can see it is not being set within any configuration files of the 3rd-party project, and doing a global search through all files (via the Finder) for #define __LP64__does not reveal to me where this is being defined by the system.
我正在 OSX 10.6 上以 32 位模式构建一个 3rd 方库（库是 Xerces 2.8）。我已经确定__LP64__设置了预处理器定义。但是，据我所知，它没有在 3rd-party 项目的任何配置文件中设置，并且对所有文件（通过 Finder）进行全局搜索#define __LP64__并没有向我揭示这是由系统。
I am building the library via makeat the command line (Xcode is not involved).
我正在通过make命令行构建库（不涉及 Xcode）。
I would like to know where __LP64__is defined - and what its purpose is, given that I am building the project in 32-bit mode.
我想知道在哪里__LP64__定义 - 以及它的目的是什么，因为我正在以 32 位模式构建项目。
回答by Jonathan Grynspan
It's defined automatically by the compiler rather than in any header. If it's set, you're building for 64-bit targets.
它是由编译器自动定义的，而不是在任何头文件中。如果已设置，则您正在为 64 位目标构建。
(A header coulddefine it if the compiler hasn't already, though it shouldn't. If you think this is the case, add #define __LP64__to your code, and look at the error during preprocessing to determine the location of the previous define.)
（如果编译器还没有定义它，则标头可以定义它，尽管它不应该。如果您认为是这种情况，请添加#define __LP64__到您的代码中，并在预处理期间查看错误以确定前一个定义的位置。）
