dbgcomp

This built-in predicate is obsolete!

Description

The generation of debug instruction is switched on by default, and is only switched off using nodbgcomp/0 or else using set_flag(debug_compile, off). This can be reversed using dbgcomp/0 or else using set_flag(debug_compile, on).

Predicates that have been compiled without debug instructions cannot be traced by the debugger (only entering and leaving such a predicate can be shown).

On the other hand, this code uses less space and runs slightly faster than code with debug instructions. So it makes sense to compile well-tested predicates without debug instructions.

Note however that predicates with debug instructions that are called by predicates without debug instructions are invisible to the debugger.

Modes and Determinism

• dbgcomp is det

Examples

Success:
      [eclipse]: dbgcomp, [user].
       p :- writeln(hello).
       user compiled 60 bytes in 0.02 seconds.
      [eclipse]: nodbgcomp, [user].
       q :- writeln(hello).
       % generated code is smaller
       user compiled 44 bytes in 0.00 seconds.
      [eclipse]: trace.
      yes.
      Debugger switched on - creep mode
      [eclipse]: p.
        (1) 0  CALL   p (dbg)?- creep
      B (2) 1  CALL   writeln(hello) (dbg)?- creep
      hello
      B (2) 1  EXIT   writeln(hello) (dbg)?- creep
        (1) 0  EXIT   p (dbg)?- creep
      yes.
      [eclipse]: q.
      N (1) 0  CALL   q (dbg)?- creep  % the inside of q/0
      hello                            % is invisible
      N (1) 0  EXIT   q (dbg)?- creep  % to the debugger
      yes.

See Also