Hey all.
I need to trace / debug a CGI script which basically involves lots of
'print DEBUG_FH'.
I noticed the existence of the Devel::Trace module which allows you to
trace your
perl script to STDERR
eg,
perl -d:Trace myprog.pl
However, since my program is a CGI, I've come across a few problems.
(1) The perl -d:<module> construct only works for Devel::Module
modules.
(2) The Devel::Trace module only traces to STDERR
(3) How do I launch my CGI with '-d' and have my tracing go to a log
file?
To solve this, I did the following:
(1) Implement a local DB::DB function which performs the tracing to
module mytrace;
sub DB::DB()
{
... trace code which traces to $_TRACE_FH if $_TRACE
}
sub trace_to
{
open( $_TRACE_FH, "$logfile");
$_TRACE = 1;
}
(2) Start debugging via the command line
#!perl -d -w
(3) Configure APACHE to disable the perl interactive debugger
SetENV PERL5DB ""
This works, however it would be neater if there was a command in perl
where
I could enable 'debug' and hence start tracing from a point. While not
wasting
CPU cycles when debugging isn't enabled.
PS. I tried printing '$^D' but it was always zero. (not undef)
changing it
obviously didn't have the effect I could hope for. I presume the
'$^D' is
relative to the -D flag, not the -d flag.
Cheers.
David
