Setting [PERL_DL_NONLAZY] forces the loader to load up all functions at once, so that it can ensure that it really does have code for all the functions it claims to have code for; this is usually what you want to do when testing. #### PERL_DL_NONLAZY Set to "1" to have Perl resolve all undefined symbols when it loads a dynamic library. The default behaviour is to resolve symbols when they are used. Setting this variable is useful during testing of extensions, as it ensures that you get an error on misspelled function names even if the test suite doesn't call them.