I've set up a page containing a table of C data types and their Clarion equivalents. For the most part this contains the list of types as explained by Carl Barnes in his 2005 ClarionMag article series on compiling C code in Clarion. I'd be interested to hear from anyone who's tried this with C8.
I've added one item to Carl's table: an entry on how to handle "pointer to a pointer" situations, specifically dereferenced cstring pointers. The example comes from John Taylor's article "Embedding The SQLite Engine In Clarion Applications".