I’ve been using Boost’s serialization library with MSVC 7.1 (the first time that I’ve used it). For most of my project I put the load / save function declaration in the class header (the .h file) and the definitions in the .cpp file – VC 7.1 allows this for templated functions, unlike some older compilers. In debug mode this compiled and linked fine except for abstract base classes – through trial and error I found that for abstract classes the functions had to be defined in the .h file to avoid linker errors. My project built fine in Debug mode and I then tried to compile / link it in Release mode – this threw up quite a few LNK2001 errors relating to just a few of the serialization load / save functions in just some of the classes – most of the classes that declared the load / save functions evidently linked fine (as they all did in Debug mode). After much double checking of the compile / link project configurations I tried the following: 1. I removed the BOOST_CLASS_EXPORT(etc) declaration at the bottom of the .h files in which the load / save functions were not linking. On recompiling / linking most of the linker errors were gone, but a few remained. 2. For the remaining classes that were not still not linking, I moved the load / save functions from the .cpp file into the .h file (these were not abstract classes). This fixed the remaining linker errors and my application compiled / linked / ran fine. I can't see why this occurred. I haven’t checked yet (it’s very time consuming to rebuild this application) but possibly option (2) would have worked for all the affected classes. For most of this project, the load / save functions remain defined in the .cpp file and clearly link fine in both debug and release configurations. Before someone asks, I did complete clean / rebuilds for both configurations – anybody any ideas? andy :-) -- ___________________________________________________________ Sign-up for Ads Free at Mail.com http://promo.mail.com/adsfreejump.htm