Older versions of SWI-Prolog had individual limits for all three (local, global and trail) stacks that were controlled using set_prolog_stack/2 as well as the command line options -L, -G and -T.

In recent version the stack limit is controlled by a single limit per thread that is controlled by the Prolog flag stack_limit and the command line argument --stack_limit=size, where size is a number that is optionally postfixed with one of BKMG for bytes, Kbytes Mbytes or Gbytes. Note that digit grouping may be used to write large integers. For example, setting the limit to 10Gb may use

set_prolog_flag(stack_limit, 10 000 000 000).

Calls to set_prolog_stack/2 that set the limit are translated to setting the Prolog flag and printing a deprecated warning.

Note that using a flag implies that new threads inherit the limit from the thread that creates the new thread. In old versions new threads always started with the default limits or the limits provided at the command line.