SWI-Prolog -- prolog:message_line

Documentation
- Reference manual
  - Built-in Predicates
    - Exception handling
      - Printing messages
        
        print_message/2
        
        print_message_lines/3
        
        message_hook/3
        
        thread_message_hook/3
        
        message_property/2
        
        message_line_element/2
        
        message_prefix_hook/2
        
        message_to_string/2
        
        version/0
        
        version/1
        
        Printing from libraries
- Packages

prolog:message_line_element(+Stream, +Term)

This hook is called to print the individual elements of a message from print_message_lines/3. This hook is used by e.g., library library(ansi_term) to colour messages on ANSI-capable terminals.