nullptr_t
Header: <stddef.h>
nullptr_t is the type of the predefined null pointer constant, nullptr. It is a distinct type that is not itself a pointer type. It can be implicitly converted to any pointer type or bool, and the result is the null pointer value of that type or false respectively. No type other than nullptr_t itself can be converted or explicitly cast to nullptr_t.
# Declarations
typedef typeof(nullptr) nullptr_t;
(since C23)
# Example
#include <stddef.h>
#include <stdio.h>
#define DETECT_NULL_POINTER_CONSTANT(e) \
_Generic(e, \
void* : puts("void*"), \
nullptr_t : puts("nullptr_t"), \
default : puts("other") \
)
int main()
{
DETECT_NULL_POINTER_CONSTANT(((void*)0));
DETECT_NULL_POINTER_CONSTANT(0);
DETECT_NULL_POINTER_CONSTANT(nullptr);
}