---
name: "Imager::Probe"
section: "3pm"
platform: "linux"
package: "libimager-perl"
version: "1.027+dfsg-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Imager::Probe"
---

# Imager::Probe(3pm)

hot needle of inquiry for libraries

## NAME

Imager::Probe - hot needle of inquiry for libraries

## SYNOPSIS

```
  require Imager::Probe;
  my %probe =
    (
     # short name of what we're looking for (displayed to user)
     name => "FOO",
     # pkg-config lookup
     pkg => [ qw/name1 name2 name3/ ],
     # perl subs that probe for the library
     code => [ \&foo_probe1, \&foo_probe2 ],
     # or just: code => \&foo_probe,
     inccheck => sub { ... },
     libcheck => sub { ... },
     # search for this library if libcheck not supplied
     libbase => "foo",
     # library link time options, uses libbase to build options otherwise
     libopts => "-lfoo",
     # C code to check the library is sane
     testcode => "...",
     # header files needed
     testcodeheaders => [ "stdio.h", "foo.h" ],
    );
  my $result = Imager::Probe->probe(\%probe)
    or print "Foo library not found: ",Imager::Probe->error;
```

## DESCRIPTION

Does the probes that were hidden in Imager's *Makefile.PL*, pulled out so the file format libraries can be externalized.

The return value is either nothing if the probe fails, or a hash containing:

- •

  `"INC"` - `"-I"` and other C options

- •

  `"LIBS"` - `"-L"`, `"-l"` and other link-time options

- •

  `"DEFINE"` - `"-D"` options, if any.

The possible values for the hash supplied to the **probe()** method are:

- •

  `"pkg"` - an array of *pkg-config* names to probe for.  If the *pkg-config* checks pass, `"inccheck"` and `"libcheck"` aren't used.

- •

  `"inccheck"` - a code reference that checks if the supplied include directory contains the required header files.

- •

  `"libcheck"` - a code reference that checks if the supplied library directory contains the required library files.  Note: the *Makefile.PL* version of this was supplied all of the library file names instead.  `"libcheck"` can also be an arrayref of library check code references, all of which must find a match for the library to be considered "found".

- •

  `"libbase"` - if `"inccheck"` is supplied, but `"libcheck"` isn't, then a `"libcheck"` that checks for `"lib"`*libbase$Config{\_a}* and `"lib"`*libbase*.*$Config{so}* is created.  If `"libopts"` isn't supplied then that can be synthesized as `"-l`*libbase*`"`. `"libbase"` can also be an arrayref of library base names to search for, in which case all of the libraries mentioned must be found for the probe to succeed.

- •

  `"libopts"` - if the libraries are found via `"inccheck"`/`"libcheck"`, these are the `"-l"` options to supply during the link phase.

- •

  `"code"` - a code reference to perform custom checks.  Returns the probe result directly.  Can also be an array ref of functions to call.

- •

  `"testcode"` - test C code that is run with Devel::CheckLib.  You also need to set `"testcodeheaders"`.

- •

  `"testcodeprologue"` - C code to insert between the headers and the main function.

- •

  `"incpath"` - `$Config{path_sep}` separated list of header file directories to check, or a reference to an array of such.

- •

  `"libpath"` - `$Config{path_sep}` separated list of library file directories to check, or a reference to an array of such.

- •

  `"alternatives"` - an optional array reference of alternate configurations (as hash references) to test if the primary configuration isn't successful.  Each alternative should include an `"altname"` key describing the alternative.  Any key not mentioned in an alternative defaults to the value from the main configuration.

## AUTHOR

Tony Cook \<tonyc@cpan.org\>, Arnar M. Hrafnkelsson