unsupported %;€l—Рzѕ”Кe¶…6 ёЫWyLZ7яО „н?НАЛ?ч;#!/usr/bin/perl eval 'exec /usr/bin/perl -S $0 ${1+"$@"}' if $running_under_some_shell; BEGIN { pop @INC if $INC[-1] eq '.' } =head1 NAME diagnostics, splain - produce verbose warning diagnostics =head1 SYNOPSIS Using the C pragma: use diagnostics; use diagnostics -verbose; enable diagnostics; disable diagnostics; Using the C standalone filter program: perl program 2>diag.out splain [-v] [-p] diag.out Using diagnostics to get stack traces from a misbehaving script: perl -Mdiagnostics=-traceonly my_script.pl =head1 DESCRIPTION =head2 The C Pragma This module extends the terse diagnostics normally emitted by both the perl compiler and the perl interpreter (from running perl with a -w switch or C), augmenting them with the more explicative and endearing descriptions found in L. Like the other pragmata, it affects the compilation phase of your program rather than merely the execution phase. To use in your program as a pragma, merely invoke use diagnostics; at the start (or near the start) of your program. (Note that this I enable perl's B<-w> flag.) Your whole compilation will then be subject(ed :-) to the enhanced diagnostics. These still go out B. Due to the interaction between runtime and compiletime issues, and because it's probably not a very good idea anyway, you may not use C to turn them off at compiletime. However, you may control their behaviour at runtime using the disable() and enable() methods to turn them off and on respectively. The B<-verbose> flag first prints out the L introduction before any other diagnostics. The $diagnostics::PRETTY variable can generate nicer escape sequences for pagers. Warnings dispatched from perl itself (or more accurately, those that match descriptions found in L) are only displayed once (no duplicate descriptions). User code generated warnings a la warn() are unaffected, allowing duplicate user messages to be displayed. This module also adds a stack trace to the error message when perl dies. This is useful for pinpointing what caused the death. The B<-traceonly> (or just B<-t>) flag turns off the explanations of warning messages leaving just the stack traces. So if your script is dieing, run it again with perl -Mdiagnostics=-traceonly my_bad_script to see the call stack at the time of death. By supplying the B<-warntrace> (or just B<-w>) flag, any warnings emitted will also come with a stack trace. =head2 The I Program While apparently a whole nuther program, I is actually nothing more than a link to the (executable) F module, as well as a link to the F documentation. The B<-v> flag is like the C directive. The B<-p> flag is like the $diagnostics::PRETTY variable. Since you're post-processing with I, there's no sense in being able to enable() or disable() processing. Output from I is directed to B, unlike the pragma. =head1 EXAMPLES The following file is certain to trigger a few errors at both runtime and compiletime: use diagnostics; print NOWHERE "nothing\n"; print STDERR "\n\tThis message should be unadorned.\n"; warn "\tThis is a user warning"; print "\nDIAGNOSTIC TESTER: Please enter a here: "; my $a, $b = scalar ; print "\n"; print $x/$y; If you prefer to run your program first and look at its problem afterwards, do this: perl -w test.pl 2>test.out ./splain < test.out Note that this is not in general possible in shells of more dubious heritage, as the theoretical (perl -w test.pl >/dev/tty) >& test.out ./splain < test.out Because you just moved the existing B to somewhere else. If you don't want to modify your source code, but still have on-the-fly warnings, do this: exec 3>&1; perl -w test.pl 2>&1 1>&3 3>&- | splain 1>&2 3>&- Nifty, eh? If