Almost all of the Win32-specific extensions make use of some Win32 API function calls. Many of these extensions exist only because Perl does not have any native way of calling these functions. This is where the Win32::API extension comes into play.
This extension provides a facility to make calls into the Win32 API. Specifically, the extension enables a Perl script to make any call into any dynamic link library (DLL). These DLLs are not limited to only Win32-specific libraries; any DLL can be used.
A word of warning regarding the Win32::API extension: This extension gives full, unlimited access to any DLL that a user can find. This can easily cause damage to your computer by corrupting data files, the Registry, and hard drives; ...