No::Worries::Warn(3)

💖 No::Worries::Warn(3) — warning handling without worries 💖

okay so bestie, this is a page from the User Contributed Perl Documentation (we love a community-contributed moment) and it's about making Perl warnings not be a whole dramatic situation. let's get into it 🫶

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✨ SYNOPSIS ✨

  use No::Worries::Warn qw(warnf handler);

  if (open($fh, "<", $path)) {
      ... so something in case of success ...
  } else {
      warnf("cannot open(%s): %s", $path, $!);
      ... do something else in case of failure ...
  }

  $ ./myprog
  myprog: cannot open(foo): No such file or directory

  $ NO_WORRIES=cluck ./myprog
  myprog: cannot open(foo): No such file or directory at myprog line 16
      main::test() called at ./myprog line 19

literally the glow-up from "huh?" to "ohhhh i see exactly where it went wrong" 💅

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🌸 DESCRIPTION 🌸

So this module eases warning handling by providing a convenient wrapper around warn() with a sprintf()-like API. and the way that warnf() is to warn() what printf() is to print()? iconic. it also trims leading and trailing spaces, which is honestly the self-care every warning deserves ✨

it also provides a handler for warn() that prepends a prefix ($No::Worries::Warn::Prefix) to all warnings. it also uses the "NO_WORRIES" environment variable to find out if Carp's carp() or cluck() should be used instead of warn(). finally, the wrapper can be told to also log warnings to syslog (see $No::Worries::Warn::Syslog) 👑

and the best part? this handler can be installed simply by importing it:

  use No::Worries::Warn qw(warnf handler);

alternatively, bestie, it can be installed "manually" (yes, the quotes are doing a lot of work there):

  use No::Worries::Warn qw(warnf);
  $SIG{__WARN__} = \&No::Worries::Warn::handler;

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🦋 FUNCTIONS 🦋

This module provides the following functions — and no, none of them are exported by default, you gotta ask for them by name 🎀

• warnf(MESSAGE) — report a warning described by the given MESSAGE
• warnf(FORMAT, ARGUMENTS...) — idem but with a sprintf()-like API
• handler(MESSAGE) — $SIG{__WARN__} compatible warning handler (this function cannot be imported — it's giving exclusive, invite-only energy 🙈)

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💜 GLOBAL VARIABLES 💜

This module uses the following global variables (none of them being exported, same rule as above):

• $Prefix — prefix to prepend to all warnings (default: the program name 🏷️)
• $Syslog — true if warnings should also be sent to syslog using No::Worries::Syslog's syslog_warning() (default: false — so, off unless you say so 💤)

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🌈 ENVIRONMENT VARIABLES 🌈

This module uses the "NO_WORRIES" environment variable to control how warnings should be reported. Supported values are:

• "carp" — Carp's carp() will be used instead of warn()
• "cluck" — Carp's cluck() will be used instead of warn()

so basically you literally just set an env var and the whole vibe of your warnings changes. no code edits. no cap. 🔥

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👑 SEE ALSO 👑

Carp, No::Worries, No::Worries::Die, No::Worries::Syslog — the whole friend group, go say hi 🫶

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🎀 AUTHOR 🎀

Lionel Cons <http://cern.ch/lionel.cons>

Copyright (C) CERN 2012-2019

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okay that's the whole page, and before you go: this beauty is perl v5.32.1, dated 2021-10-18, and it lives at No::Worries::Warn(3) — go forth and warn responsibly, bestie 💖✨🍓