# <stdbool.h>

<head><title>&lt;stdbool.h&gt;</title></head>

# `<stdbool.h>`

[added with
[C99](https://docs.qualcomm.com/doc/80-N3040-23/topic/c_lib_over.html#C99)]

* * *

Include the standard header **`<stdbool.h>`**
to define a type and several macros suitable for writing Boolean tests.
The standard header `<stdbool.h>` is available even in a
[freestanding implementation](https://docs.qualcomm.com/doc/80-N3040-23/topic/c_lib_over.html#freestanding%20implementation).

        /* MACROS */
    #define bool _Bool [keyword in C++]
    #define false 0 [keyword in C++]
    #define true 1 [keyword in C++]
    #define __bool_true_false_are_defined 1
    
        /* TYPES */
    typedef i-type bool; [keyword in C++]Copy to clipboard

## `__bool_true_false_are_defined`

    #define __bool_true_false_are_defined 1Copy to clipboard

The macro yields the decimal constant `1`.

## `bool`

    #define bool _Bool [keyword in C++]Copy to clipboard

The macro yields the type `_Bool`.

## `false`

    #define false 0 [keyword in C++]Copy to clipboard

The macro yields the decimal constant `0`.

## `true`

    #define true 1 [keyword in C++]Copy to clipboard

The macro yields the decimal constant `1`.

* * *

See also the
**[Table of Contents](https://docs.qualcomm.com/doc/80-N3040-23/topic/c_index.html#Table%20of%20Contents)** and the
**[Index](https://docs.qualcomm.com/doc/80-N3040-23/topic/_c_index.html)**.

*[Copyright](https://docs.qualcomm.com/doc/80-N3040-23/topic/c_crit_pjp.html) © 1992-2006by P.J. Plauger. All rights reserved.*

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Last Published: Oct 06, 2026

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