# stdbool.h Types and Values

## bool Macro

Alternate type name to _Bool.

Include

<stdbool.h>

Remarks

The bool macro allows the use of an alternate type name to _Bool.

## true Macro

Symbolic form of the true state.

Include

<stdbool.h>

Remarks

The true macro provides a symbolic form of the true state that can be used with objects of type _Bool and is defined as the value 1.

## false Macro

Symbolic form of the false state.

Include

<stdbool.h>

Remarks

The false macro provides a symbolic form of the false state that can be used with objects of type _Bool and is defined as the value 0.

## _ _bool_true_false_are_defined Macro

Flag to indicate that the boolean macros are defined and are usable.

Include

<stdbool.h>

Remarks

The _ _bool_true_false_are_defined macro is set if the bool, true and false macros are defined and are usable. It is assigned the value 1 in the header, but this macro along with the bool, true and false macros may be undefined and potentially redefined by the program.