i created a new carbon static library project, then added a cpp file and its header file in it. I wrote a line of code in the cpp file: "#include <Files.h>". But when i built it, the xcode reported a error: Files.h: No such file or directory.
I am new to xcode, so maybe my question is so stupid, but i still hope somebody can give me a answer! Thanks a lot.

Tried #include <Carbon/Files.h>?

You also might need to add the Carbon framework to your project.

Thank u for ur answer.
But after i tried ur method, the problem still exists.
i use the function "HOpenDF" in my code, it is declared in the header file "Files.h", right?
However, after i deleted the code "#include <Files.h>", i can build my code successfully with a warning: " 'HOpenDF' is deprecated (declared at /Developer/SDKs/MacOSX10.4u.sdk/..blahblah.../Headers/Files.h").
So i added this resulted static library (*.a) to my main program (a C++ command-line tool), then built my main program successfully.But, when i ran its product, it failed with a message: "Zerolink:unknown symbol '_HOpenDF' ". It is more confused that it can work without any error when i debug my main program step by step in the debug status.
so i really need ur advice, thank you again.

You need to add the Carbon framework to your main program.

thank u, it really works.