How do you convert PostgreSQL internal binary field to C datatypes

Does someone out there has some example(s) of converting the 
PostgreSQL's internal (network byte order) representation of  float4, 
flost8, date, datetime and timestamp into Win32 float, double, CTime or 
any Win32 date/time construct under Intel x86 h/w architecture?

Andrew McNamara in previous post suggested that there are answers in the 
server source codes.  But for a beginner like me, even though I have 
extensive coding experience in C, C++ and Java, such undertaking for a 
significant product like PostgreSQL is a bit overwhelming for now.

I really do want to explore the usage of PostgreSQL further!  So any 
help will be greatly appreciated. 

Jeff,