Parameters that can be Queried Only

Prolog flags can be used to effect the changes listed above, or to ask about the current values of those parameters. In addition, you can use prolog_flag/2 (not prolog_flag/3) to make the following queries using the flag names listed below:

Flag

Purpose

add_ons

What add-on products are statically linked into to Prolog system?

host_type

What is the host-type?

quintus_directory

What is the absolute name of the Quintus directory, where is the root of the entire Quintus Installation hierarchy?

runtime_directory

What is the absolute name of the directory where all Prolog executables reside? In the Runtime System, it is expected that this value will be overwritten, using qsetpath when the runtime system is installed (see too-too-qgetpath and too-too-qsetpath). This flag is used to define file_search_path(runtime,RuntimeDir).

version

What version of Prolog is being run?

system_type

development

Use prolog_flag/2 to make queries, prolog_flag/3 to make changes.