Oooooops....
Thanks Peter, there is a difference:
For the VMS debug option in the C compiler, I believe /noopt is recommended,
although that is (again, belief, from memory) not mandatory nor forced. If
memory serves, we are still building perl with /noopt due to various hairy
compiler bugs, but again, I'm out of the loop here.
Anyway, my statement about the vms /debug switch not affecting the speed of
execution is wrong, if it disables compiler optimization. Sorry about that.
SO, when we are speaking of the VMS DEBUGGER:
If (perl is built with optimization ENABLED ... at any level)
And
(/debug is set with /noopt)
THen
it is likely to cause some noticeable performance degradation.
For some reason, I was thinking about the linker when I was writing, and
there the /debug switch will only have the effects I described (modulo this
optimization difference).
I'll side with Jordan, in that once the 5.6 stuff becomes really stable, we
can afford to build without /debug, but until then, I'd vote for keeping
/debug enabled, as fixing obscure problems is more important than slightly
faster execution.
Then, of course, there is the wonderful, murphyian effect, that enabling the
/debug switch removes certain bugs....
Best, [EMAIL PROTECTED]
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
Sent: Friday, March 10, 2000 4:18 PM
To: [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED]
Subject: RE: 5.6.0 RC1 and the perl debugger
Carl Friedberg wrote:
> wait, are we talking VMS debug support, or PERL debug support.
>
> VMS debug support should NOT change the execution speed; it makes the
image
> a bit larger (the symbol tables are loaded in virutal memory) but I've
never
> found an "debug" image to be any different in speed than one without
debug.
> In fact, somewhere buried in ancient code, I have a little "trick" which
> flips the debug bit in the header so you can turn on debugging dynamically
> by remote control...
>
> I assumed Dan was speaking about the Perl debugger, which is a pile of
> psuedocode?
That's right and `perl -d myscript` will run (via a bunch of evals and
other hairy stuff) irrespective of whether there are VMS DEBUG symbols
in your PERL.EXE. [.lib]perl5db.pl is a monument to obfuscated (and *quite*
useful) perl code.
If it does make for a speedup (you and Dan seem to be at odds over the
matter)
then I'd say let's try to have CC/DEBUG builds turned off by default but
still requestable.
Peter Prymmer
