什么是之间__ preTTY_FUNCTION__，__FUNCTION__，__func__区别？ [英] What's the difference between __PRETTY_FUNCTION__, __FUNCTION__, __func__?
问题描述
有什么__功能的 __ preTTY_FUNCTION __ ，的区别__ ， __ FUNC __ ，和他们在哪里记录？我该如何决定使用哪一个呢？
What's the difference between __PRETTY_FUNCTION__, __FUNCTION__, __func__, and where are they documented? How do I decide which one to use?
推荐答案
__ FUNC __ 是扩展到包含函数名称时，它是一个字符数组变量隐式声明的标识符一个函数的内部使用。它被添加到C C99。从 C99 的§6.4.2.2/ 1：
__func__ is an implicitly declared identifier that expands to a character array variable containing the function name when it is used inside of a function. It was added to C in C99. From C99 §6.4.2.2/1:
标识符 __ __ FUNC 被隐式由译者声明那样的话，紧随其后的每个函数定义的左大括号，声明
The identifier
__func__is implicitly declared by the translator as if, immediately following the opening brace of each function definition, the declaration
static const char __func__[] = "function-name";
出现，其中函数名是词法，封闭函数的名称。此名称是函数的朴实名称。
appeared, where function-name is the name of the lexically-enclosing function. This name is the unadorned name of the function.
请注意，这不是一个宏，它有preprocessing期间没有特殊含义。
Note that it is not a macro and it has no special meaning during preprocessing.
__ FUNC __ 添加到C ++在C ++ 11，在那里它被指定为包含实现德科幻奈德字符串（C ++ 11§8.4.1[ dcl.fct.def.general] / 8），这是不是很在C规格（原来的建议添加有用 __ __ FUNC 来C ++是的 N1642 ）。
__func__ was added to C++ in C++11, where it is specified as containing "an implementation-defined string" (C++11 §8.4.1[dcl.fct.def.general]/8), which is not quite as useful as the specification in C. (The original proposal to add __func__ to C++ was N1642).
__ __功能为pre-标准的扩展，一些C编译器的支持（包括gcc和Visual C ++）;在一般情况下，你应该使用 __ FUNC __ 在那里支持，并且只使用 __功能__ 如果您使用的编译器不支持它（例如，Visual C ++，它不支持C99和尚不支持所有的C ++ 0x的，不提供 __ FUNC __ ）。
__FUNCTION__ is a pre-standard extension that some C compilers support (including gcc and Visual C++); in general, you should use __func__ where it is supported and only use __FUNCTION__ if you are using a compiler that does not support it (for example, Visual C++, which does not support C99 and does not yet support all of C++0x, does not provide __func__).
__ preTTY_FUNCTION __ 是gcc的一个扩展，主要是一样的 __功能__ ，但对于C ++功能它包含包括函数的签名功能中的pretty的名称。 VISUAL C ++也有类似的（但不完全相同）扩展， __ __ FUNCSIG 。
__PRETTY_FUNCTION__ is a gcc extension that is mostly the same as __FUNCTION__, except that for C++ functions it contains the "pretty" name of the function including the signature of the function. Visual C++ has a similar (but not quite identical) extension, __FUNCSIG__.
对于非标准宏，你会想咨询你的编译器的文档。 Visual C ++的扩展名包括C ++编译器的的MSDN文档中的predefined宏。 GCC的文档扩展在GCC文档的网页。描述功能名称作为字符串。
For the nonstandard macros, you will want to consult your compiler's documentation. The Visual C++ extensions are included in the MSDN documentation of the C++ compiler's "Predefined Macros". The gcc documentation extensions are described in the gcc documentation page "Function Names as Strings."
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