---
name: "IPC::Run::Debug"
section: "3pm"
platform: "linux"
package: "perl-ipc-run"
version: "20260402.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/IPC::Run::Debug"
---

# IPC::Run::Debug(3pm)

debugging routines for IPC::Run

## NAME

IPC::Run::Debug - debugging routines for IPC::Run

## SYNOPSIS

```
   ##
   ## 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.
```

## DESCRIPTION

Controls IPC::Run debugging.  Debugging levels are now set by using words, but the numbers shown are still supported for backwards compatibility:

```
   0  none         disabled (special, see below)
   1  basic        what's running
   2  data         what's being sent/received
   3  details      what's 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
```

The `"none"` level is special when the environment variable IPCRUNDEBUG 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.

To do this in a script, here's a way that allows it to be overridden:

```
   BEGIN {
      unless ( defined $ENV{IPCRUNDEBUG} ) {
         eval 'local $ENV{IPCRUNDEBUG} = "none"; require IPC::Run::Debug'
            or die $@;
      }
   }
```

This should force IPC::Run to not be debuggable unless somebody sets the IPCRUNDEBUG flag; modify this formula to grep `@ARGV` if need be:

```
   BEGIN {
      unless ( grep /^--debug/, @ARGV ) {
         eval 'local $ENV{IPCRUNDEBUG} = "none"; require IPC::Run::Debug'
            or die $@;
      }
   }
```

Both of those are untested.

## AUTHOR

Barrie Slaymaker \<barries@slaysys.com\>, with numerous suggestions by p5p.