Config::Extensions − hash lookup of which core extensions were built.


    use Config::Extensions '%Extensions';
    if ($Extensions{PerlIO::via}) {
        # This perl has PerlIO::via built


The Config::Extensions module provides a hash %Extensions containing all the core extensions that were enabled for this perl. The hash is keyed by extension name, with each entry having one of 3 possible values:

The extension is dynamically linked


The extension is pure perl, so doesn’t need linking to the perl executable


The extension is statically linked to the perl binary

As all values evaluate to true, a simple "if" test is good enough to determine whether an extension is present.

All the data uses to generate the %Extensions hash is already present in the "Config" module, but not in such a convenient format to quickly reference.


Nicholas Clark <>

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