Functions can be used by C code by just prepending export to the beginning of function definitions. Structs and datatypes have similar ease.

The C language allows you to provide a pointer to a function, just like a pointer to a variable. In both cases, a C pointer contains the address and the type information about the entity being pointed ...

The researchers claimed some areas of success, particularly in C. However, Codex still trumped it in other languages. "Notably, PolyCoder outperforms Codex and all other models in the C language ...