Not all functionality of the C-interface is provided, but as
PlTerm and term_t are
essentially the same thing with automatic type-conversion between the
two, this interface can be freely mixed with the functions defined for
plain C.
Using this interface rather than the plain C-interface requires a
little more resources. More term-references are wasted (but reclaimed on
return to Prolog or using PlFrame).
Use of some intermediate types (functor_t etc.) is not
supported in the current interface, causing more hash-table lookups.
This could be fixed, at the price of slighly complicating the interface.
The mechanisms outlined in this document can be used for static linking with the SWI-Prolog kernel using swipl-ld(1). In general the C++ linker should be used to deal with the C++ runtime libraries and global constructors.
The current interface is entirely defined in the .h file
using inlined code. This approach has a few advantages: as no C++ code
is in the Prolog kernel, different C++ compilers with different
name-mangling schemas can cooperate smoothly.
Also, changes to the header file have no consequences to binary compatibility with the SWI-Prolog kernel. This makes it possible to have different versions of the header file with few compatibility consequences.