If that works, then you can likely do the same in Perl. But as I don't know your C++ code to access that memory mapped file, you will have to find out yourself what API calls C# uses and how to access these from Perl.

CPAN has some modules for memory mapping files, see Mmap, maybe you find something there. Or alternatively, maybe you can open the file just as a file, see open. In any case, you will have to find out what works for you, because I'm not going to learn what Windows API the C# code uses.