View Compilation Error

0_0_21181072_17327.cpp: In instantiation of 'segt<T>::segt(const T*, unsigned int) [with T = int]':
0_0_21181072_17327.cpp:42:20:   required from here
0_0_21181072_17327.cpp:16:38: error: 'memset' was not declared in this scope
 memset(__data, 0, __n * 2 * sizeof(T));
                                      ^