What are the dependencies of a FreePascal GUI app written with Lazarus?

Question

I know that FreePascal apps for Linux are statically linked. I imagine that there are some low-level APIs required. Is this just GTK for GUI applications? I assume a command-line app wouldn't have the same dependencies.

Where can I find a way to determine which LCL classes require which underlying APIs?

Edit: Vitaly wanted to know what I found with his answer.

With a small console app: ldd confirmed that it was a statically linked executable.
strace was more interesting. A console-only application showed no open files. I guess it's totally self contained.

With a simple GUI application, ldd showed some dynamic linking, and strace's output showed many "open"s.

It'll still take a little more research before I'm comfortable with this.

Answer 1

Since they are statically linked, exactly what kind of dependencies could they have?..

However you can try to work it out with a several methods...

1. ldd <executable> (just to be sure that your binary is not dynamically linked)
2. strace <executable> > log.file 2&>1 && cat log.file | grep open

Where can I find a way to determine which LCL classes require which underlying APIs?

From my point of view, this purpose requires some hard work. I'd advice to try systemtap for the one.