When exporting functions from a library, there are 2 things you must take in account:
The calling conventions are controlled by the modifiers cdecl, popstack, pascal, safecall, stdcall and register. See section 6.3, page 396 for more information on the different kinds of calling scheme.
The naming conventions can be controlled by 2 modifiers in the case of static libraries:
For more information on how these different modifiers change the name mangling of the routine section 6.2, page 387.
Remark: If in your unit, you use functions that are in other units, or system functions, then the C program will need to link in the object files from these units too.