Lazarus vs QtCreator GUI programms
lazarus / 39-Graphics

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djdjdjole · 2012-11-19 16:22

When I start Lazarus built (or some demo) GTK program (ARM board), for
the first time, after booting the system, then it needs 30 seconds  to
start (same or subsequent program start quickly after that probably
because GTK libraries are already loaded).
When I built Linux with Qt support and start QtCreator built demo
programs, it start in two seconds, even for the first time.
Althaugh I don't know QtCreator, I understood that programs created
that way need -qws options to start and it seems to me that they don't
need X (at least, I didn't start X explicitely).
That raises few questions to me :
- what should happened if I build Qt with Lazarus. Should it require X
to run (X, itself, requires 10 seconds to start for the first time)?
- should I expect huge starting times (when using Lazarus) like in GTK
case ?
- is there some equivalent to -qws option when using Lazarus ?
- does it mean that at least regarding program start time Lazarus
cannot compete QtCreator ?

Appretiate any help

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Blaazen · 2012-11-19 16:50

I run Lazarus with Qt (on KDE4 desktop) and startup of Lazarus and
QtCreator apps is ±same. The Lazarus is a little slower (probably
because of larger executables) but usually the startup time is ~ 0,5
sec. for both (start from DoubleCommander). Both was empty or almost
empty projects.

@ Althaugh I don't know QtCreator, I understood that programs created
that way need -qws options to start and it seems to me that they don't
need X (at least, I didn't start X explicitely).

I don't know whether Qt in some special configuration does not require
X.

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djdjdjole · 2012-11-19 20:06

Thank you Blaazen for swift replay. Here is the link regarding Qt in
embedded environments: http://qt-project.org/doc/qt-4.8/qt-embedded-
running.html. And one more matter. All the Qt examples that was built
together when building linux (using Buildroot), had to be started with
the "-qws" option, otherwise they simply don't work - indicating qws
missing error. And no X was started before running those demos (like I
had to do with GTK demos).
I think that the  Lazarus is particularly oriented to desktops, so it
uses Qt "over" X. QtCreator seems to somehow "override" X (at least
for embedded environments), by using own server (Qt window server
-qws).
If I am right, it seems, that when using Lazarus (for Qt apps) I also
need X started and that is 10 seconds more - compared to QtCreator
application startup time. That is quite a time for embedded
applications.

Regards

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djdjdjole · 2012-11-19 20:34

What I also forgot to emphasize in previous reply is the fact that in
desktops - X is already started (during system boot up). Also GTK or
Qt libraries (depending on desktop type - meaning GNOME or KDE) are
already loaded.
So it seems to me that it is not adequate to compare application
startup times in desktops (all libararies are present) with those in
embedded - where startup times are of interest while measuring from
the moment of pressing power on switch.

Regards