I have been using heavily a custom frontend to mathematica based on mathlink. I derived it from http://library.wolfram.com/infocenter/Demos/174/frontend.c?file_id=4692 . I just learned that mathlink was replaced by WSTP. Is there a dictionary to translate my old program to WSTP or maybe a WSTP version of the mentioned frontend example?
It is not necessary to translate anything. Mathematica 10 comes with two developer kits. One is called "WSTP" and one is called "MathLink". The only difference is in the naming conventions used by the functions. Simply use the one called "MathLink".
It may be necessary to adjust one thing though:
The default MathLink API version in Mathematica 10 is
4. When compiling older programs, it's better to use the older version
3 API. Do this by compiling everything with
-DMLINTERFACE=3 (pass this command line option to the compiler) and by linking against the libraries ending in