> I'm more familiar using a C, or C++, API by calling
> functions than embedding SQL statements in my source.

This might let you prefer using the API-calls.

> The Interbase 6 Developers Guide suggests using the
> API has some advantages over using the embedded SQL.

I would guessthat you might get problems when e.g. trying to pass
statement handles as parameters while using embedded SQL.

> You can write your own application using C or C++, or
> another programming language,and embed SQL statements in
> the code.

You can also have SQL-Statements within your code when using API. But
they are strings there.

> Advantages of using the InterBase API
>
> Simplification of compiling procedure—no precompiler

This might be relecant when using some IDE qhich does not really
support external precompilers.

> Does "API application" refer to using C style function
> calls to communicate to the database?

Yes.

> If so, where is the C, or preferably the C++, API
> described?

It's the API-Guide from the Interbase 6 Documentation.

> I've downloaded the new 1.5.0.4920 Windows embedded
> executable today. I don't see any C header (.h) files
> among those expanded when I unzipped the embedded
> Windows distribution.

It should be part of the server-Archive.

One addition to consider: Using embedded SQL does allow you to have
your SQL-Statements analysed at compile time. Besides an small
performance gain (which i would estimate as minor) this does check
your application for correct SQL - including misspelled names.

Elmar