What header file needs to be included for using nullptr in g++?

Question

I am using g++ 4.4.1 and want to use nullptr, but I am not being able to find which header file is required to be included. It does not seem to be keyword either, because my attempt to use it is rejected as

error: 'nullptr' was not declared in this scope

Answer 1

GCC 4.4.1 does not support nullptr.

Support for nullptr will be included in the upcoming GCC 4.6.0 release: http://gcc.gnu.org/gcc-4.6/changes.html

Improved experimental support for the upcoming C++0x ISO C++ standard, including support for nullptr (thanks to Magnus Fromreide), noexcept, unrestricted unions, range-based for loops (thanks to Rodrigo Rivas Costa), implicitly deleted functions and implicit move constructors.

In the meantime, if you want to experiment with nullptr you can try the workaround in this SO question:

Can nullptr be emulated in GCC?