7.16 Boolean type and values <stdbool.h>
The header <stdbool.h> defines four macros.
The macro
bool
expands to _Bool.
The remaining three macros are suitable for use in #if preprocessing directives. They are
true
which expands to the integer constant 1,
false
which expands to the integer constant 0, and
__bool_true_false_are_defined
which expands to the integer constant 1.
Notwithstanding the provisions of 7.1.3, a program may undefine and perhaps then redefine the macros bool, true, and false.[1]
Footnotes