Fwd: How to use langmap?

[Tu Do]

Which is that you want to know?

o How to load configuration file?

o How to write langmap variable?

I want to know the syntax of the configuration file (how to write) and how to load it. There's no document to show how to properly write one.

Would be nice to know how to extend the default one. Your suggetion in previous email seems to override the default value. Is there a way to make it like shell environment variable, i.e. langmap=$langmap:\cpp\:.c++.cc.hh:\?