If I compile code using the Visual C++ 2008 compiler, do I need to have the matching service pack of the runtime library for that compiled code to run correctly?
Suppose I compile code with Visual C++ 2008 compiler (any edition). Will this work with the SP1 VC++ 2008 runtime library?
Conversely, if I compile code with a Visual C++ 2008 SP1 compiler (any edition). Will this work with the RTM VC++ 2008 runtime library?
Probably.
This is part of the reason that MS introduced the idea of Side by Side assemblies. Your code specifies its preference, and the OS gets to offer the assemblies it currently has available. If there is a match, your code runs. If not, no luck.
You do have to follow all the usual guidelines for application manifests and probably make the installation of the runtime library available in your installation package in any case.