问题描述
我在此处询问了有关 assert ，它在标准中以宏而非函数的形式实现.
I asked a question here about assert which is implemented in the standard as a macro, not a function.
这引起了我一个问题，因为assert似乎是采用参数形式的函数:assert(true)因此，我尝试将其用作:std::assert(true)，当然是一个宏，它没用.
This had caused me an issue because the way that assert appears to be a function in the way it takes a parameter: assert(true) Thus I tried to use it as: std::assert(true) and of course being a macro that didn't work.
我的问题是:标准库是否提供了其他任何带有参数的宏?
My question is this: Are there any other macros provided by the standard library which would appear as functions that take parameters?
推荐答案
如果我们看一下[header]第5和6段，我们就有
If we look at [headers] paragraphs 5 and 6 we have
在C中定义为函数的名称应在C ++标准库中定义为函数.
Names that are defined as functions in C shall be defined as functions in the C++ standard library.
因此，如果在C中将其定义为宏，则它将在C ++中为宏.虽然有一些例外.摘自[support.runtime]第7和8段
So, if it is defined as a macro in C, it will be a macro in C++. There are a couple of exceptions though. from [support.runtime] paragraphs 7 and 8
标头<cstdbool>和标头<stdbool.h>不应定义名为bool，true或false的宏.
The header <cstdbool> and the header <stdbool.h> shall not define macros named bool, true, or false.
尽管这些例外也包含在[headers]/7中
Although that those exceptions are covered by [headers]/7 as well
还有一个例外，即每[c.math]/10
There is also an exception that all classification macros defined in 7.12.3 Classification macros be overloaded by functions per [c.math]/10
int fpclassify(float x);
bool isfinite(float x);
bool isinf(float x);
bool isnan(float x);
bool isnormal(float x);
bool signbit(float x);
bool isgreater(float x, float y);
bool isgreaterequal(float x, float y);
bool isless(float x, float y);
bool islessequal(float x, float y);
bool islessgreater(float x, float y);
bool isunordered(float x, float y);
int fpclassify(double x);
bool isfinite(double x);
bool isinf(double x);
bool isnan(double x);
bool isnormal(double x);
bool signbit(double x);
bool isgreater(double x, double y);
bool isgreaterequal(double x, double y);
bool isless(double x, double y);
bool islessequal(double x, double y);
bool islessgreater(double x, double y);
bool isunordered(double x, double y);
int fpclassify(long double x);
bool isfinite(long double x);
bool isinf(long double x);
bool isnan(long double x);
bool isnormal(long double x);
bool signbit(long double x);
bool isgreater(long double x, long double y);
bool isgreaterequal(long double x, long double y);
bool isless(long double x, long double y);
bool islessequal(long double x, long double y);
bool islessgreater(long double x, long double y);
bool isunordered(long double x, long double y);
这篇关于什么是标准调用实际上是宏的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！