“布尔”是C ++中的基本数据类型吗? [英] Is 'bool' a basic datatype in C++?
问题描述
我在编写一些代码时有这个疑问。 布尔是C ++标准中定义的基本数据类型,还是编译器提供的某种扩展?我对此表示怀疑,因为Win32的 BOOL只是long的typedef。如果我做这样的事情,也会发生什么事:
I got this doubt while writing some code. Is 'bool' a basic datatype defined in the C++ standard or is it some sort of extension provided by the compiler ? I got this doubt because Win32 has 'BOOL' which is nothing but a typedef of long. Also what happens if I do something like this:
int i = true;
是否总是保证变量i的值为1还是再次取决于编译器我在用 ?进一步对于某些接受BOOL作为参数的Win32 API,如果我传递bool变量会发生什么情况?
Is it "always" guaranteed that variable i will have value 1 or is it again depends on the compiler I am using ? Further for some Win32 APIs which accept BOOL as the parameter what happens if I pass bool variable?
推荐答案
bool是其中的基本数据类型C ++。将 true
转换为整数类型将产生1,而将 false
转换为整数(4.5 / 4和4.7 / 4 )。在C语言中,直到C99都没有bool数据类型,人们所做的事情是
bool is a fundamental datatype in C++. Converting true
to an integer type will yield 1, and converting false
will yield 0 (4.5/4 and 4.7/4). In C, until C99, there was no bool datatype, and people did stuff like
enum bool {
false, true
};
Windows API也是如此。从C99开始,我们将 _Bool
作为基本数据类型。包括 stdbool.h
将 typedef #define
变为 bool
并提供常量 true
和 false
。由于现有代码的兼容性问题,他们没有将bool设为基本的数据类型(因此也没有成为关键字)。
So did the Windows API. Starting with C99, we have _Bool
as a basic data type. Including stdbool.h
will typedef #define
that to bool
and provide the constants true
and false
. They didn't make bool a basic data-type (and thus a keyword) because of compatibility issues with existing code.
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