PL_ACTION_TRACE
Start Prolog tracer PL_ACTION_DEBUG
Switch on Prolog debug mode PL_ACTION_BACKTRACE
Print backtrace on current output stream. The argument (an int) is the number of frames printed. PL_ACTION_HALT
Halt Prolog execution. This action should be called rather than Unix exit() to give Prolog the opportunity to clean up. This call does not return. PL_ACTION_ABORT
Generate a Prolog abort. This call does not return. PL_ACTION_BREAK
Create a standard Prolog break environment. Returns after the user types control-D. PL_ACTION_SYMBOLFILE
The argument (a char *) is considered to be hold the symbolfile for further incremental loading. Should be called by user applications that perform incremental loading as well and want to inform Prolog of the new symbol table.