```{index} single: Config::Extensions ``` # Config::Extensions hash lookup of which core extensions were built. ## SYNOPSIS ```perl use Config::Extensions '%Extensions'; if ($Extensions{PerlIO::via}) { # This perl has PerlIO::via built } ``` ## DESCRIPTION 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: - dynamic The extension is dynamically linked - nonxs The extension is pure perl, so doesn't need linking to the perl executable - static 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. ## AUTHOR Nicholas Clark