Because you can place only one function declaration macro in each template function, you get only one environment variable, which controls the trace output from every instantiation of that particular template function. It is not trivial to determine which instantiation of a template function produced a particular trace message. If this information is required, you need to get it yourself, using a mechanism such as RTTI, and include it in the trace macro call. This is a known limitation of the Execution Tracing package.