A foreign resource that wants to be shared between several SICStus runtimes must somehow know which SICStus runtime is calling it so that it can make callbacks using the SICStus API into the right SICStus runtime. In addition, the foreign resource may have global variables that should have different values depending on which SICStus runtime is calling the foreign resource.
A header file is generated by splfr when it builds a
foreign resource (before any C code is compiled). This header file
provides prototypes for any foreign-declared function, but it
also provides other things needed for multiple SICStus runtime
support. This header file must be included by any C file that contains
code that either calls any SICStus API function or that contains any of
the functions called by SICStus. See The Foreign Resource Linker.