Syntax
nullptr | (since C++11) |
Explanation
The keyword nullptr
denotes the pointer literal. It is a prvalue of type std::nullptr_t
. There exist implicit conversions from nullptr
to null pointer value of any pointer type and any pointer to member type. Similar conversions exist for any null pointer constant, which includes values of type std::nullptr_t
as well as the macro NULL
.
Example
Demonstrates how nullptr allows forwarding via a template function.
#include <cstddef> #include <iostream> template<class F, class A> void Fwd(F f, A a) { f(a); } void g(int* i) { std::cout << "Function g called\n"; } int main() { g(NULL); // Fine g(0); // Fine Fwd(g, nullptr); // Fine // Fwd(g, NULL); // ERROR: No function g(int) }
Output:
Function g called Function g called Function g called
Keywords
See also
implementation-defined null pointer constant (macro constant) | |
(C++11) | the type of the null pointer literal nullptr (typedef) |
References
- C++11 standard (ISO/IEC 14882:2011):
- 4.10 Pointer conversions [conv.ptr]
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