6.15.1 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 (note the leading two underscore characters) 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.