Config

use Config; if ($Config{cc} =~ /gcc/) {
 print "This perl was built by GNU C.\n";
}
use Config qw(myconfig config_sh config_vars);
print myconfig(); # like perl -V without a pattern print config_sh(); # gives absolutely everything config_vars qw/osname osvers archname/;

The configuration mechanism that builds and installs Perl assembles a wealth of information about your system. The Config module exports by default a tied hash variable named %Config, which provides access to over 900 different configuration values. (These values are also available through Perl's -V:PATTERN command-line switch.) Config also provides three functions that give more shell-like access to these values, as shown above. For instance, that last call might print out:

osname="openbsd"; osvers="2.6"; archname="openbsd.sparc-openbsd";

The module's online documentation describes the configuration variables and their possible values. Be aware that if you move your perl executable to a system other than the one on which it was built, these values may not reflect the current reality; for instance, if you're running a Linux or a Solaris binary on a BSD system.