In file included from /usr/include/c++/4.4/unordered_map:35, from expand.cpp:5: /usr/include/c++/4.4/c++0x_warning.h:31:2: error: #error This file requires compiler and library support for the upcoming ISO C++ standard, C++0x. This support is currently experimental, and must be enabled with the -std=c++0x or -std=gnu++0x compiler options. expand.cpp: In function 'int main()': expand.cpp:11: error: 'unordered_map' was not declared in this scope expand.cpp:11: error: expected primary-expression before ',' token expand.cpp:11: error: expected primary-expression before '>' token expand.cpp:11: error: 'stringsMap' was not declared in this scope