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.\" ========================================================================
.\"
.IX Title "IPC::Run::Debug 3pm"
.TH IPC::Run::Debug 3pm "2018-05-23" "perl v5.26.2" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.SH "NAME"
IPC::Run::Debug \- debugging routines for IPC::Run
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 7
\&   ##
\&   ## Environment variable usage
\&   ##
\&   ## To force debugging off and shave a bit of CPU and memory
\&   ## by compile\-time optimizing away all debugging code in IPC::Run
\&   ## (debug => ...) options to IPC::Run will be ignored.
\&   export IPCRUNDEBUG=none
\&
\&   ## To force debugging on (levels are from 0..10)
\&   export IPCRUNDEBUG=basic
\&
\&   ## Leave unset or set to "" to compile in debugging support and
\&   ## allow runtime control of it using the debug option.
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
Controls IPC::Run debugging.  Debugging levels are now set by using words,
but the numbers shown are still supported for backwards compatibility:
.PP
.Vb 7
\&   0  none         disabled (special, see below)
\&   1  basic        what\*(Aqs running
\&   2  data         what\*(Aqs being sent/received
\&   3  details      what\*(Aqs going on in more detail
\&   4  gory         way too much detail for most uses
\&   10 all          use this when submitting bug reports
\&      noopts       optimizations forbidden due to inherited STDIN
.Ve
.PP
The \f(CW\*(C`none\*(C'\fR level is special when the environment variable \s-1IPCRUNDEBUG\s0
is set to this the first time IPC::Run::Debug is loaded: it prevents
the debugging code from being compiled in to the remaining IPC::Run modules,
saving a bit of cpu.
.PP
To do this in a script, here's a way that allows it to be overridden:
.PP
.Vb 6
\&   BEGIN {
\&      unless ( defined $ENV{IPCRUNDEBUG} ) {
\&         eval \*(Aqlocal $ENV{IPCRUNDEBUG} = "none"; require IPC::Run::Debug"\*(Aq
\&            or die $@;
\&      }
\&   }
.Ve
.PP
This should force IPC::Run to not be debuggable unless somebody sets
the \s-1IPCRUNDEBUG\s0 flag; modify this formula to grep \f(CW@ARGV\fR if need be:
.PP
.Vb 5
\&   BEGIN {
\&      unless ( grep /^\-\-debug/, @ARGV ) {
\&         eval \*(Aqlocal $ENV{IPCRUNDEBUG} = "none"; require IPC::Run::Debug"\*(Aq
\&         or die $@;
\&   }
.Ve
.PP
Both of those are untested.
.SH "AUTHOR"
.IX Header "AUTHOR"
Barrie Slaymaker <barries@slaysys.com>, with numerous suggestions by p5p.