Question

This is relevant only for calling exported SystemVerilog functions from C code. The caller is responsible for allocating any actual arguments that are passed by reference.

Static allocation requires knowledge of the relevant data type. If such a type involves SystemVerilog packed arrays, their actual representation needs to be known to C code; thus, the file svdpi_src.h needs to be included, which makes the C code implementation-dependent and not binary compatible.

Sometimes binary compatibility can be achieved by using dynamic allocation functions. The functions svSizeOfLogicPackedArr() and svSizeOfBitPackedArr() provide the size of the actual representation of a packed array, which can be used for the dynamic allocation of an actual argument without compromising the portability (see Annex E.11.11). Such a technique does not work if a packed array is a part of another type.