c('PL_action')

Documentation
- Reference manual
  - Foreign Language Interface
    - The Foreign Include File
      - Environment Control from Foreign Code
        
        PL_action()
- Packages

Availability:C-language interface function

int PL_action(int, ...)

Perform some action on the Prolog system. int describes the action. Remaining arguments depend on the requested action. The actions are listed below:

PL_ACTION_TRACE: Start Prolog tracer (trace/0). Requires no arguments.
PL_ACTION_DEBUG: Switch on Prolog debug mode (debug/0). Requires no arguments.
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. The argument (an int) is the exit code. See halt/1.
PL_ACTION_ABORT: Generate a Prolog abort (abort/0). This call does not return. Requires no arguments.
PL_ACTION_BREAK: Create a standard Prolog break environment (break/0). Returns after the user types the end-of-file character. Requires no arguments.
PL_ACTION_GUIAPP: Windows: Used to indicate to the kernel that the application is a GUI application if the argument is not 0, and a console application if the argument is 0. If a fatal error occurs, the system uses a windows messagebox to report this on a GUI application, and otherwise simply prints the error and exits.
PL_ACTION_TRADITIONAL: Same effect as using --traditional. Must be called before PL_initialise().
PL_ACTION_WRITE: Write the argument, a char * to the current output stream.
PL_ACTION_FLUSH: Flush the current output stream. Requires no arguments.
PL_ACTION_ATTACH_CONSOLE: Attach a console to a thread if it does not have one. See attach_console/0.
PL_GMP_SET_ALLOC_FUNCTIONS: Takes an integer argument. If TRUE, the GMP allocations are immediately bound to the Prolog functions. If FALSE, SWI-Prolog will never rebind the GMP allocation functions. See mp_set_memory_functions() in the GMP documentation. The action returns FALSE if there is no GMP support or GMP is already initialised.