Here is a small sample from CPAN of some of the ways to interpret your question:

Data::Struct
Simple struct building
Data-Struct-1.701 - 23 Nov 2011 - Johan Vromans

SOOT::Struct
Perl interface to generate new C-level struct types
SOOT-0.17 - 25 Dec 2011 - Steffen Müller

Win32::API::Struct
C struct support package for Win32::API
Win32-API-0.68**** (3 Reviews) - 10 Apr 2012 - Cosimo Streppone

Thrift::Parser::Type::Struct
Struct type
Thrift-Parser-0.03 - 16 Sep 2012 - Eric Waters

Class::Struct::FIELDS
Combine Class::Struct, base and fields
Class-Struct-FIELDS-1.1 - 05 Jul 2001 - B. K. Oxley (binkley)

Class::Struct
declare struct-like datatypes as Perl classes
perl-5.16.1*** (9 Reviews) - 08 Aug 2012 - Ricardo SIGNES

Inline::SLang::Struct
Support for structures
Inline-SLang-1.00 - 04 Jan 2005 - Douglas Burke

Inline::Struct
Manipulate C structures directly from Perl.
Inline-Struct-0.06*** (1 Reviews) - 11 Jun 2001 - Neil Watkiss