Perl has its own C API for extensions called XS. You'd have to implement this from the Pascal side to call perl modules (not to mention the rest of the Perl C API that the module might call). What would be more likely to be a workable solution would be to write a C extension that creates a perl interpreter and link against that from your Pascal (and then you could send perl code from your pascal to load the module and do all the xls mucking). See perldoc perlembed for more details.