Re: About GPL and proprietary software

> Would a perl application using DBI have a similar problem? Or how would
> one then legally use PHP with MySQL without GPL-ing your product and
> without buying MySQL commercial license?

I don't think so, especially since you can ship them separately.  If I
just have code telling my computer to use the DBI module, but don't
actually ship the DBI module, I'm not using any MySQL code.  The end-user
is the one combining the works (they could just as easily have dropped in
a closed-source driver with the same interface), which you have permission
to do under the GPL.

When programming w/ C it's different because #include literally includes
MySQL's header files into your code, thus making the binary a derivative
work.  The source is not a derivative work, since it doesn't make use of
MySQL code, but the binary is, subjecting it to the GPL (which means you
have to distribute code).

Jon