Just a curios question, how slackers get to find out all the packages dependencies quickly? Juts hunt them down via google, project main page etc? I find using arch linux package listing pretty good:

http://www.archlinux.org/packages.ph...tupdate=&pp=50

But i dont know how comprehensive is the dependencies listed and what is the assumptions it make, but it looks like a fast way to find out things.

Sorry. I misunderstood your query.

It really is pretty simple. If the package comes with Slackware, its deps are met by Slackware.
For external software, the prefered method is to roll your own. Either by simply compiling and installing the software or by creating your own package for it. This way, you know the deps by reading the project page.
If you must use third party packages, the package maintainer should give you a list of deps if there are any that aren't met by slackware. Preferably in a slack-required file in the install directory of the tar-ball or, alternatively, on the website where you downloaded the file.

ldd `which command`

well , i do understand reading from the project page IS the way, but i was thinking on how to find out dependencies of a certain apps really quick, like the sample from Archlinux?

Run it and it will tell you which libraries it can't find
Also, most README.TXT or INSTALL.TXT files tell you the requeriments of the software.