include/import native old .cpp and .h

[hadler]

hi i have a old sintax native c++ project, with function and define, in some .cpp and .h files.
Now i'm developing a visual c++ clr in visual studio 2008 and i've tried to #include .cpp or .h file but compiler foud some error regard old sintass.
i'm not able to understand why there are this error and i prefer to create a managed dll of this files to implement in my project.
is possible this?
or what is the most easy method to implement this file without error?
tnx

[Alex F]

The whole project must be compiled with the same /clr option. You cannot mix old and new syntax in the same project.
If you don't want to rewrite old code, make oldsyntax Class Library from it, and use it in a new projects.