SecurezeroMemory equivalent function in linux c++11 code

Hello we have written c++ code which compiles both on windows and ubuntu I want to use secure function memset_s for zeroing out buffers in my app.

Both windows & Ubuntu (16.04) PC does not include definition of STDC_LIB_EXT1 macro so I am not able to use memset_s provided by C++11.

On windows I have SecureZeroMemory which prevents compiler optimization. On Ubuntu 16.04 (with gcc version 5.4 )I am looking for SecureZeroMemory equivalent library function available in gcc or c++11(which will prevent compiler optimization).

Thanks in advance