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2022-07-19Use Prolog string buffer marks.John Ankarström
Speaking of unclear documentation, it is not obvious whether it is necessary for programs calling into Prolog to manually mark and release strings. I suppose that it should be, if the same logic that applies to terms apply to strings. On the other hand, the stack in which the strings are stored belongs to Prolog, and there is nothing that would prevent Prolog from cleaning up the strings when called at a later time. I am not sure. But better safe than sorry, I guess. The Mark class acts like the Frame class. The constructor and destructor are equivalent to the PL_STRINGS_MARK and PL_STRINGS_RELEASE macros. Unlike for 34c3280, I did not notice any differences in memory usage after this change. Perhaps that is because it has no effect; perhaps it is because Prolog's stack is very big.
2022-07-19Fix Prolog memory leaks.John Ankarström
Apparently foreign frames ARE needed when calling Prolog from C. The official documentation is very terse and could make this clearer. To summarize, whenever a term is created (e.g., PL_new_term_refs), its reference count is increased by one. It is garbage-collected when its reference count hits zero. But the reference count is never decreased unless (a) control returns to Prolog after executing a foreign predicate -- which does not happen in my application -- or (b) the foreign frame in which the term was created is closed. In other words, terms must be created within a foreign frame. This is achieved by initializing a Frame object before creating the term and destroying it once the term has served its purpose. The destructor for Frame does not DISCARD the frame, only CLOSE it. The former would also invalidate all data bound by the terms, which is usually undesirable.
2022-07-18Solve compiler warnings.John Ankarström
2022-07-18Avoid leak in Prolog interface.John Ankarström
PL_new_atom(_wchars) creates an atom with a reference count of one, which is never decreased, and the atom is thus never garbage collected.
2022-07-17Prefer f() over f(void).John Ankarström
f(void) is a C-ism that is valid but unnecessary in C++.
2022-07-17Update type names and variable prefixes.John Ankarström
2022-07-17Name function arguments in headers.John Ankarström
This is obviously a lot less obtuse.
2022-07-17Add const to pointers, update spacing.John Ankarström
It seems that "right-spaced" pointers are more widely used among C++ programmers.
2022-07-17Add const to places.John Ankarström
Note that I did NOT add const to non-pointer/non-reference arguments in function declarations (without a following definition), as they do not mean anything there.
2022-07-17Use SWI-Prolog's wide-character functions.John Ankarström
This avoids the use of TsmFromSz.
2022-07-16Formatting.John Ankarström
2022-07-16Rewrite TszFromSz as TsmFromSz.John Ankarström
I.e. using std::basic_string<TCHAR> instead of TCHAR *. This removes all unmanaged frees.
2022-07-15Split defs.h into separate header files.John Ankarström
This is feasible now that the makedeps script exists to automatically manage build dependencies (see 6034fe2, d00f8b3).