You are not showing source code which causes this problem. The identifier
, is not found, but the source code you show uses
which will be compiled with "windows.h":
is the macro
used to implement window procedure
(in a lame C++ way, in my opinion
In response to the follow-up question: yes, this token-pasting '##' operator you never mentioned before. It is explained here:
All this preprocessor activity and this way of message handling is such a lame! Can I unsee it?