Hi Paul,

> Is there any documentation anywhere for the Firebird client API for
> use from C/C++.

> I presume I need to use the 'ibase.h' file (and associated files),
> but I can't find any documentation on the functions in there.

This is the most complete guide:

http://www.ibphoenix.com/downloads/60ApiGuide.zip

It's still the InterBase 6 API guide, but very little has changed.
Consult the Firebird Release Notes to make sure.

If you're a C++ programmer, I think you could also greatly benefit
from ibpp, a C++ Firebird API (a frontend to the C API):

http://sourceforge.net/projects/ibpp


Greetings,
Paul Vinkenoog