bool

C++ Specific

booldeclarators**;**

This keyword is an integral type. A variable of this type can have values true and false. All conditional expressions now return a value of type bool. For example, i!=0 now returns true or false depending on the value of i.

The values true and false have the following relationship:

!false == true
!true == false

In the following statement:

if (expres1) statement1; 

If expres1 is true, statement1 is always executed; if expres1 is false, statement1 is never executed.

When a postfix or prefix ++ operator is applied to a variable of type bool, the variable is set to true. The postfix or prefix -- operator cannot be applied to a variable of this type.

The bool type participates in integral promotions. An r-value of type bool can be converted to an r-value of type int, with false becoming zero and true becoming one.

END C++ Specific

Microsoft Specific

In Visual C++4.2, the Standard C++ header files contained a typedef that equated bool with int. In Visual C++ 5.0 and later, bool is implemented as a built-in type with a size of 1 byte. That means that for Visual C++ 4.2, a call of sizeof(bool) yields 4, while in Visual C++ 5.0 and later, the same call yields 1. This can cause memory corruption problems if you have defined structure members of type bool in Visual C++ 4.2 and are mixing object files (OBJ) and/or DLLs built with the 4.2 and 5.0 or later compilers.

END Microsoft Specific