Re: Uncertainty about pkg-config

[Havoc Pennington <hp redhat com>]

On Sat, 2004-07-03 at 19:22, Ray Simard wrote:
> For a while now I've been building packages from Gnome CVS. I admit 
> to being rather new to the environment.
> 
> I'm not certain what the appropriate version information in the 
> naming for the .pc files in ../pkgconfig is supposed to be. 
> Specifically, is gnome-foo 2.6 supposed to install a 
> gnome-foo.2.6.pc or gnome-foo-2.0.pc?

This number should change when ABI compatibility is broken. e.g. you
would change from GTK+ 1.x to GTK+ 2.x, but not GTK+ 2.2 to GTK+ 2.4.

See http://ometer.com/parallel.html for the rationale.

> Several packages have failed to build because PKG_CHECK_MODULES was 
> expecting one thing and the installed .pc file was named 
> differently, even though the actual version of the packaged 
> specified as required was at or greater than the requirement.

The actual version of the package is inside the .pc file in the Version
field, and that's where PKG_CHECK_MODULES gets the version. The version
number in foo-2.pc is not the version of the release, but the "ABI
version" - it's part of the _name_ of the library. foo-1 and foo-2 could
be replaced by "foo" and "foo-nextgeneration" or something for example,
or just "foo" and "bar" - it's just naming different things something
different.

So e.g. in PKG_CHECK_MODULES(foo-2 >= 3.0) you have "foo-2" is the
library name and "3.0" is the version.

Havoc