The compiler option --pending_instantiations only makes any sense when used with C++ code. It cannot have any effect on C code. Indeed, when passed as an option to a compilation of C code, the compiler will stop and emit an error, "pending instantiations option can be used only when compiling C++" This is troublesome when trying to compile a mixture of C and C++ files in CCS. If the user wishes to use the option --pending_instantiations, they cannot just add this option to the global compiler options list; they must add this option individually to each C++ file.