[solved] QT with QT_NO_STL?

Question

Hello ARCH people.
I lately experienced a problem converting from std::string to QString compiling QT Applications. The following error i get:
error: conversion from `std::string' to non-scalar type `QString' requested
By searching google and reading a bit, i've found out that this problem seems to occur if QT_NO_STL is used as a compile option to QT.
Is there any specific reason why ARCH has set the option QT_NO_STL? Is it set, or am i wrong in this case?
I've never had this problem in any other distribution, so i'm asking you here for advice. Of course, i'd like if i dont have to recompile QT completely.
TIA,
STi

Answer 1

phrakture wrote:c++ exceptions are poor for performance.
No, you are wrong. How often do you throw exceptions? They are slower than error codes when they do occur, but faster when they don't occur (because you don't check for them with an "if"). So in average they are FASTER.
Enabling the exceptions doesn't mean it removes the use of throw and catch, it just means that Qt doesn't throw errors... you can still:
QString blah("some string");
throw std::exception(blah.latin1());
if you want to.... disabling the exception is only in the Qt library...
No, you are wrong. If you disable exceptions when compiling Qt, this means that you can't reliably throw an exception from a slot (a signal handler). If you do throw, then Qt's destructors won't be called when unwinding happens -> crash.
You will be able to use exceptions provided they don't go through Qt's code. This is restricting, actually. You can't say it's not an issue.
because you are assuming that enabling stl is 100% good with no downsides....
I can't see the downside. Enabling stl means anabling just a few additional functions in Qt, this is not bloat. Afterall, enabling stl doesn't cause any additional runtime dependency, because STL is contained in headers and you have to link to libc++ no matter what options you specify.
I am not claiming to be educated in it either, it's just that I trust the judgement calls made on these packages seeing as they work with no real hiccups....
I guess you don't develop in C++, so you should listen when somebody with greater knowledge on this subject tries to teach you something.
personally I hate c++ exceptions.... yes it's easy to use a try/catch block... but it just seems lazy to me.  It's personal preference.
Have you read Herb Sutter's "Exceptional C++?" Writing good exception-enabled code is actually a lot of additional work. But it usually leads to better, much more reliable code.
On another note, you were not "Just asking why Arch disables exceptions and stl in case of Qt?"....
vicious wrote:Seem the packager has NO idea about C++ and Qt. Qt should have another maintainer.
A much better course of action would have been "hey why is this done?" and await a response.... but the immediate calls for mutiny made me balk.
I agree here. I shouldn't talk this way. It's just the people who try to pretend they are more knowledgable than they really are who drive me crazy.
I understand it's your preference not to use exceptions. But it doesa lot of harm to disable exceptions when compiling libraries for people who want to use exceptions.
tyrade time
In my opinion, the key thing open source has going for it is this sort of "anyone can contribute" thing.  It's the exact opposite of the way us american's are taught to believe... here it's compitition that drives someone to make a good product better, it is not done for the sake of doing it.  OSS is very existensialist in a way.... now this is great, and I love the fact that someone like me could send a minor patch to linus, or kieth packard, or someone and have it accepted into code that millions of people use.  A big problem errupts when "hey here's something you did wrong, I fixed it" turns to "everything you do is wrong, I'm forking your project"... that's the attitude I get from this thread.... not an email to the maintainer or anything, but a flat out cry for a replacement....
If you want something to strive, help it, don't beat it down... you water your plants when they begin wilt, you don't chuck them in the trash and buy a cactus....
I agree completely. But I'm sure I'm not the only one responsible for the attitude you get from this thread.