1.12 Version 2.5 Release Notes

Version 2.5 is an intermediate release on the path from 2.1 to 3.0. All changes are to the foreign-language interface, both to user- and system predicates implemented in the C-language. The aim is twofold. First of all to make garbage-collection and stack-expansion (stack-shifts) possible while foreign code is active without the C-programmer having to worry about locking and unlocking C-variables pointing to Prolog terms. The new approach is closely compatible to the Quintus and SICStus Prolog foreign interface using the +term argument specification (see their respective manuals). This allows for writing foreign interfaces that are easily portable over these three Prolog platforms.

According to the current plan, ISO compliant exception handling and hooks for source-code debugging will be added before the system will be called 3.0.

Apart from various bug fixes listed in the Changelog file, these are the main changes since 2.1.0:

• ISO compatibility
  Many ISO compatibility features have been added: open/4, arithmetic functions, syntax, etc.
• WIN32
  Many fixes for the Win32 (NT, '95 and win32s) platforms. Notably many problems related to pathnames and a problem in the garbage collector.
• Performance
  Many changes to the clause indexing system: added hash-tables, lazy computation of the index information, etc.
• Portable saved-states
  The predicate qsave_program/[1,2] allows for the creating of machine independent saved-states that load very quickly.