I'm reposting this:

I have been unable to find the answer to this problem in either the
OPS or the API pdf -- help would be greatly appreciated.

I am using Firebird 1.5 -- the embedded server. I am able to query
against the employee.fdb database using isql, so I know that much is
working.
(Parenthetically, it seems I can connect with any user/password
combination, even non-existent ones. Can someone explain that behavior
to me?)

I used the makefile.msc included in the examples directory to build
api1.exe and api2.exe with the Microsoft compiler (version 7.0).
When I try to run them, I get:

Your user name and password are not defined. Ask your database
administrator to set up a Firebird login.

I tried setting my system environment variables ISC_USER and
ISC_PASSWORD to SYSDBA and masterkey, respectively, as described in
the documentation. (I set them at the system level.) When I look at
these variables in my DOS command prompt, they are indeed set.

It looks like I could set the user and password within the C code
(using one of the API functions), but I assume it is not necessary to
modify the source in order to get these examples to work.

Can somebody give me a clue?

Thanks in advance.