[Lazarus] BreakIf

[Henry Vermaak]

On Fri, Mar 27, 2015 at 01:45:31PM +0100, JuuS wrote:
> Good morning, all...
> 
> >From my Delphi days we had the following procedure:
> 
> procedure BreakIf( b : Boolean );
> begin
>  if b then
>  asm
>    INT 3    <======debugger would then stop here
>             and one could then F8 step to the offending
>             routine based on the boolean condition passed
>  end;
> end;
> 
> I believe this is windows specific (?) and I'm now working on Linux
> machines.

On Windows you can use DebugBreak() instead of the asm.

> The question is:
> 
> This does not work in Linux and I wonder if there is a similar way to
> achieve this in Linux environment?

To be more portable, you can send the SIGTRAP signal, just make sure
that your program ignores it so it doesn't die.  Try this with/without
GDB:

program bp;
uses BaseUnix;
begin
	FpSignal(SIGTRAP, signalhandler_t(SIG_IGN));
	writeln('hi there');
	FpKill(FpGetpid, SIGTRAP); { <-- breakpoint here }
	writeln('exiting');
end.

Henry