expected string-literal before ‘)’ when using static_assert in c++17

So when I try to build my c++ application I get compile-time error in the following piece of code

static_assert(sizeof(page_id_t) == 4)

This is the error that I get expected string-literal before ‘)’

On some investigation I found out that static_assert required a message param in c++11 which was eliminated in c++17. So does it look like my application is being compiled for c++11?

In my CMakeLists.txt file I have the following lines

set(CMAKE_CXX_STANDARD 17)              
set(CMAKE_CXX_STANDARD_REQUIRED ON)

Shouldn't the above lines build my application for c++17?

Thanks!