What is the way to have a visual utility ? a custom widget ?

[tonnot]

I would want to develop an utility to (for example) opening a file, reading it, put some data in a memory region.
Must I learn how to develop a custom widget ? or there is an easiest way ?
( I want that this utility does not spent time when compiling the main project)
Thanks

[tbscope]

I would want to develop an utility to (for example) opening a file, reading it, put some data in a memory region.
Must I learn how to develop a custom widget ? or there is an easiest way ?

What do you want to do? Do you want to visualise some data? If so, try using the standard widgets.
If that doesn't suit you, you can create your own.

But for just the data handling, you don't need to create widgets.

( I want that this utility does not spent time when compiling the main project)

Please try to explain this a little bit better. I can't make anything of this.

[tonnot]

I would want to develop an utility to (for example) opening a file, reading it, put some data in a memory region.

Imagine a little element of my program that make something ( a dialog where the user open some file to import, for example)
This piece (with visual aspect, since it has a dialog with some buttons) can be a custom widget, or a dll ?

I want that this utility does not spent time when compiling the main project

Depends of my utility is either a custom widget or a dll ?
I hope that now I have explained better.

[tbscope]

I find your posts very confusing, but I'll give it a try.

You can create a dialog with standard widgets like buttons, lists, menus etc...
This can be done in a standalone program, or as a plugin or library.

For you I recommend starting a little bit easier:
http://doc.qt.nokia.com/4.6/tutorials.html

As for the second question, are you asking if there is a difference in compile speed between an application or a library?
That is not a question anyone can answer since that would be comparing apples and oranges. Yes both are fruit, bur very different.