SWI-Prolog -- prolog

Documentation
- Reference manual
  - Foreign Language Interface
    - Notes on Using Foreign Code
      - Foreign debugging functions
        
        PL_backtrace()
        
        PL_backtrace_string()
        
        PL_check_data()
        
        PL_check_stacks()
        
        prolog_debug/1
        
        prolog_nodebug/1
- Packages

Availability:built-in

prolog_debug(+Topic)

prolog_nodebug(+Topic)

Enable/disable a debug topic. Topic is an atom that identifies the desired topic. The available topics are defined in src/pl-debug.h. Please search the sources to find out what is actually printed and when. We highlight one topic here:

chk_secure(chk_secure): dd many expensive consistency checks to the system. This should typically be used when the system crashes, notably in the garbage collector. Garbage collection crashes are in most cases caused by invalid data on the Prolog stacks. This debug topic may help locating how the invalid data was created.