gcc linker error, 'not declared in this scope'

file1.cppgcc version 4.9.2..

#ifdef _WIN32__declspec(dllexport)std::vector<int> g_vDelay;#else __attribute__((visibility("default")))extern std::vector<int> g_vDelay;#endif

..

void SetDelayTimes(std::vector<int>& vDel){    g_vDelay.swap(vDel);}

..file1.cpp:386:2: error: ‘g_vDelay’ was not declared in this scopeg_vDelay.swap(vDel);^