CppCast - WxWidgets

Episode Date: January 30, 2020

Rob and Jason are joined by Vadim Zeitlin one of the maintainers of WxWidgets. They first talk about a blog post describing a fantastic bug and another responding to the changes announced by Qt. Then Vadim tells them about how he got involved contributing to WxWidgets, the cross platform C++ GUI library. News Fantastic Bugs and Where to Find Them C++ Modules conformance improvements with MSVC in VS 2019 16.5 Concepts merged to clang trunk About Qt Offering Changes 2020 Links WxWidgets WxWidgets on GitHub Sponsors Backtrace Software Crash Management for Embedded Devices and IOT Projects Announcing Visual Studio Extension - Integrated Crash Reporting in 5 Minutes

Episode 232 of CppCast with guest Vad at backtrace.io.cppcast. In this episode, we talk about fantastic bugs and changes to Qt. Then we talk to Vadim Zeitlin. Vadim talks to us about WX Widgets, the first podcast for C++ developers by C++ developers. I'm your host, Rob Irving. Joining me, my co-host, Jason Turner. Jason, how's it going today? I'm all right, Rob. How are you doing?

Doing good. Don't really have any news to share myself. Anything going on with you? Well, I do have some classes and stuff coming up, but that'll just be a sneak peek. We'll talk about that more next week. Okay, sounds good. Well, at the top of every episode,

I'd like to read a piece of feedback. We got this tweet from uh jan willmans who we've had on the show before and uh he says weird things happening on spotify and i guess he listens to the podcast on spotify we are there if you are not aware and uh apparently in addition to all these other bands he listens to, like Rush, where it's recommending, you know, listen to the best of Rush. It's saying listen to the best of Phil Nash, which is interesting. Well, it also said that Phil has like 200,000 followers, too. Yeah.

Yeah. I don't. Does Phil have other stuff on Spotify besides being on a couple of our episodes? I don't know. No. I think Phil Nash is a singer, although I'm I don't know. No. I think Phil Nash is a singer, although I'm not getting that at the moment.

Not a different Phil Nash. Convusing our Phil Nash with a different Phil Nash? Artist Phil Nash, yes. Okay. I guess that would explain it. Okay. Well, we'd love to hear your thoughts about the show. You can always reach out to us on Facebook,

Twitter, or email us at feedback at cpcast.com. And don't forget to leave us a review on iTunes or subscribe on YouTube. Joining us today is Vadim Zitlin. Vadim Adventures in Programming started with BASIC on an 8-bit microcomputer with a whopping 4 kilobytes of RAM when he was 10 years old

in the mid-80s and continued with Pascal C at the beginning of the 90s, Discovery of C++ that he has been using since then. What started as a hobby became a job when after finishing his PhD in mathematics in 2002, he founded the TT Solutions Company, providing support for open source software, and in particular, WX widgets. Almost 20 years, one marriage and three children later, Vadim still remains enthusiastic about programming in general and open source in particular, and tries to contribute to open source projects whenever possible, even if his primary focus remains on WX widgets. Vadim, welcome to the show. Thank you for having me here and

great to take place in it. So I'm curious, you say an 8-bit microcomputer with 4K of RAM, I'm curious exactly which computer that was. Nobody has heard about this one because that was one from the Soviet Russia. Oh, no, that makes it twice as interesting to actually have a small list of Soviet Russian and Polish computers that I've learned about from other guests. It must not be a very long list because there were just a couple of them. Some of them, they tend to be clones of Western computers, several of them have. Undoubtedly they were, but as we didn't know anything about Western computers,

we didn't know about that. It cost an awful amount of money, and I badgered my parents into buying it even though they couldn't afford it, really. I really needed it. It was a question of life and death. I had to have my own. I thought it was worth the investment, though. Well, I didn't think about it as an investment back then, but yes. Like that.

From a parent's perspective, yeah. Okay, well, Vadim, we've got a couple news articles to discuss, and then we'll start talking more about WX Widgets, okay? Sure. Okay, well, Vadim, we got a couple news articles to discuss, and then we'll start talking more about WX Widgets, okay? Sure. Okay, so this first one was a really long article. It was. Fantastic bugs and where to find them.

And I'll be honest, I started skimming a little bit towards the end when I started seeing just how long this article was. was, but it was interesting. It talked about just a very, very odd error where the debugger was claiming to be having an access violation at executing location zero, like 0, 0, 0 in memory. And it wound up being related to this

custom coroutines library since we don't actually have official coroutines yet. And the stack't actually have official coroutines yet, and the stack being corrupted somehow. Right, Jason? Yeah. Yes. I've seen this one. They had trouble with exception fending, actually, which was

incompatible with their coroutines implementation. The advantage of using custom stuff like custom coroutine libraries is that you get a chance to discover very interesting bugs yeah this is a little bit of a ride for me because at first i'm like well min gw has enough random bugs around threading and stuff that and i know like some people try to defend it but it really does like i have bugs that i just can't support and so i'm like yeah it's probably just a bug in MinGW.

And then I see that it involves exceptions specifically. I'm like, I hope they realize that there's two different exception models for MinGW and then get to the end. Oh, okay, they just had to switch to exception. Okay. It's a little bit of a rollercoaster ride. Yeah, a little bit. Okay, this next one is an

update from the Visual Studio C++ blog. C++ blog, C++ modules conformance improvements with the latest upcoming build, which is 2019 16.5. And, yeah, we haven't talked about modules in a while, but I think Visual Studio is one of the first compilers to have module support, and they are continuing to update it. The new things they're adding are header units,

which I don't believe we've talked about before, Jason, right? I don't know. We've covered so many articles on modules. Honestly, I don't know if header units came up. Yeah. Well, the new things are, though, header units, context-sensitive module and import keywords, global module fragments, and module partitions.

So a lot of changes coming in. We really should maybe do a deeper dive in modules, especially when it's official in C++20 and released. Yeah, they have Gabby back on or something. Yeah. Okay, next thing we have is a follow-up from our talk with Sar Raz from a few weeks ago. And this is him announcing that Concepts was officially merged into Clang Trunk. Eight days ago. Yeah.

So do we know which version it'll be available in? Is it Clang 10 or Clang 11? Do we know that yet? It is 10. It is 10. Yeah, it got ported to 10, yeah. Okay, and then last thing we have to talk about, and I'm sure our guests will have some comments on this one, Yeah, it got ported, so yeah. developer who has been using it for over 20 years, and it's kind of their response to what the Qt Foundation or company is doing. To summarize, it looks like they're trying to put some restrictions

on the open source version of Qt. Is that a good way to describe it? Like you now are going to need to have an account in order to log on and download the libraries before you didn't have to. Right. And binaries are only available to paying customers. Right. So if you want to use open source Qt, you're going to have to have an account and then download the source yourself and build it yourself. Yes. Or use Conan. That's true. That's a good point. It's quite bad, but it's not my place and Qt, but actually they do allow to download binaries. You just have to use their website.

I mean, I don't usually follow the development of Qt exactly closely, but I couldn't escape this thought because it was everywhere in all the places, in all the communities related to public switches recently. So I saw it and basically I really don't think it's the end of the world. I don't think it's going to change that much in practice, but it does show that Qt is a company, you know, they have to do their stuff and they have to monetize their users in some way. There is one thing that surprised me is that it took so long. You're surprised they didn't make this type of change years ago? Well, I could be wrong, but I don't think it's going to be the last change in Qt licensing and marketing, whatever model. Yeah, so the article that we are linking to, Rob,

does seem to overstate that. The official Qt article just says you have to have an account to download binaries. It does not say you have to have a commercial account, which is what the article you're linking to says. Okay, so they might have it wrong. But some of these things like LTS binaries are only available... Oh, and offline installers are available commercial online.

Yeah, they basically want all open source users to use their latest version. And I understand why. We as W3D developers, we want to do the same thing, of course. We want all our users to use the latest version to find the bugs as quickly as possible. The only thing is that we

don't force people to do it because, well, we can't. But if they can, I understand why we want to. And to your point that Qt has to monetize their users somehow and you expect more changes to come in the future. It's been a long ride. Like, I remember when KDE first came out

and people are like, well, I'm not going to support that because Qt is partially closed source or whatever. Like, way back in the day on Linux. It was closed source. It wasn't always Qt. It came so much later. Yeah, well, you know, in the beginning, WXVidgets and Qt were really competitors. And this hasn't been really the case since many more years because Qt has just become dominant. It's one of the main WXVidgets, of course, I'm not at all blind to that. But the thing is that

when I saw pictures from QT 3.0 I believe released, I was pretty impressed because there were like several hundred people working on QT. And compared with W2G's there are maybe a dozen of people

working on it more or less frequently enough. And only just half of really important core contributors. So you know, all this amount of people working on it more or less frequently enough. And only just half of really important core contributions. So you know, all this amount of people, you have to fund it somehow. So again, I am sure that the world just can't have the same business model, if you can call it that, as W3D does when we just give away everything that we have without any compensation, whether it's monetary or account creation and ad serving or whatever,

they are going to use these accounts for. We can allow that because, well, we don't need any money. We don't have any costs. We just do it in our own free time. And they have to find money somewhere. Right, right. Okay, well, since you just started talking a little bit about WXWidgets,

why don't you, I guess, first tell us a little bit more about what WXWidgets is in case our listeners aren't too familiar with the library. Yeah, so WXWidgets teaches that it's write once, compile anywhere framework. So this allows you to write

your C++ code for once and then compile it on all the supported platforms and have it run as a native desktop application on different platforms. Currently the main platforms are Windows, it's always Linux and different desktop environments, and MacOS. So there is some limited support for mobile platforms, but the focus has always been on the desktop. And the main difference between WSWidgets and almost all the other graphical frameworks for C++ or even other languages is that WSWidgets tends to be native. That is, we always use native widgets and we always try to integrate into the native desktop as much as possible. So we don't do our own stuff. We try to provide the common API on top of the

native API of the various platforms, which hides the difference between them, while still allowing you to access them. It's true. And provides common, high-level, much higher-level API that maps to the different APIs from the developer. And that's actually the fun part of developing. You have to sometimes get quite creative to marry different APIs from different platforms that do things sometimes in a very different way. It can be interesting. It can be challenging. And when you manage to do it nicely,

it can be also very easy. So how much does that limit you? Like, you want to add a new feature, but then say, oh, oops, it's like, you know, difficult to impossible to add this on Mac OS, but easy on Windows, so we have to leave the feature out for an hour or something like

that. This is a concern. So our typical rule of thumb is that if we can implement the feature on more than or something like that? This is a concern. So our typical rule of thumb is that if we can implement the feature on more than one platform, we're going to do it. So we're not going to implement the features which are only available on just a single. Basically, all people who use W3D don't necessarily use the same platforms

on all four sides, or many there could be. Some people only use one platform. It's true, but it's related in a minority. But people quite often use it only on a couple of platforms. So we believe that if we can provide a feature on more than one, on strictly more than one platform, it's worth doing that. Although there are some features that we just can't provide at all. For example, if you compare that with widgets with Electron,

all this web-based stuff which supports theming and arbitrary customizations of colors and whatever. Something that is not supported on the traditional desktop. So this, for example, this is something that we can't do at all. So we don't. So yeah, this approach definitely has its own limitations. But as a user, I really appreciate programs that use WXWidgets, and I think it's much nicer to have something that fits into your desktop and doesn't stand out like a software. I think it's worth pointing out that Rob and I always use Audacity for recording audio here, and if I understand correctly, that is a WXWidgets project as well. You can use WXWidgets, yes. I've never participated in the development of the project,

but I have been constantly with developers to resolve some of the issues. And by the way, if you're listening to this podcast, I've always welcomed people working on WXWidgets applications to contact us and ask us if they have any problems with WXWidgets. Because WXWidgets on its own is not very useful. It's the applications that are really the things that we are working for. I want to interrupt the discussion for just a moment

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It's free to try, minutes to set up, with no commitment necessary. Check them out at backtrace.io slash cppcast. So you're talking about some APIs that are very difficult to implement. You might only put them on the platforms you can support them on. How, as a developer, do you know this API only works on Windows and Linux, but not on Mac? And is there a way to query that or to write your code in such a way? Like, do you wind up having to if-def it for platforms, things like that? That's slightly complicated because it depends.

It actually depends on the size of the feature. If it's a huge feature and you can't really provide any reasonable fallback, we disable it at compile time. Okay. So we just, some compile time. So we just some compile time symbol which tells you if the feature is available or not. Sometimes when it's just part of a bigger class and just some part of its functionality can't be implemented, it's just a function that is tapped out to always return false. For example, say that it didn't do anything. And again, it's a judgment that we have to make on case-by-case basis and it's not always

obvious. I hope that we get it right more case-by-case basis, and it's not always obvious. I hope that we get it right more often than not, but we probably make some mistakes about this. But that's the interesting part of the work. So you have to make your judgments in each case. Right. So do you want to go over the full list of platforms that are available? I think you just said Windows, Linux, Mac.

Are there any other ones worth noting? Those are the three major ones. We actually have, well, there was, again, W3D development is not really guided by anybody, so people just do things that they want to do. And so there was a company which contributed significant development time on improving WXQT 4. So it's a kind of double interaction, you know.

So it's WXQT API implemented on top of Qt. And this project exists since several years. It was a Google Summer of Code project in New York. But as quite often with Google Summer of Code projects, it wasn't really finished during the summer. And so it wasn't really usable. But since last year, I think it is. And so for people who really want, for example, to transition from W3 to W3, or maybe from W3 to W3, that may be an interesting port to use. Then there are some legacy ports like Motif port, because apparently there are still legacy ports like MotifPort, because apparently

there are still some people using Motif. Wow, oh, okay. So these two, and there are some experimental ports which we used for some particular applications like Direct Frame Buffer, VFX, VFB, but again, it's in a very, very basic state, so it was written for a particular application, so, all the features needed by this application were implemented. So things like that. We used to have more ports. We used to have plenty of other ports.

We used to have DOS port. We used to have OS2 port. But we have finally got rid of those a few years ago. And there is also WX-Control-4, which is pretty basic and which, I don't know, can actually be used for right-maining non-toy applications.

And there is iOS-Port, which is slightly more useful because there are applications in Disney on Apple Store. Well, not many, but I know at least a couple. So it's also rather basic, but it does work and it does support. it's also rather basic, but it does

work and it does support. It's useful enough to allow you to use quite large amounts of code between your desktop and mobile versions. That's pretty cool. Yeah. So that's about it. How much effort is involved in bringing a new platform into the

WX widgets family? Like if some new desktop operating system comes out, like how many APIs do you need to go and write to make WX widgets work on that platform? It's not that difficult to have something very basic. Okay. You have to create a window. But to implement the full WX widgets API for a platform,

it's a lot of work. The API is huge. I haven't counted the number of classes and functions in it since quite some time. That's nothing. So there are some things that are due to it on the low level, but on the benefit of that, there are also some things that you don't have to write for every platform. But even the low-level parts, there are still quite a lot of things there.

So yeah, I don't want to discourage people, but it's not that easy to write for each of them. Not really, not to try, of course. But we haven't had any new ports since quite a long time. For example, I think that we'd like to have a port to Windows Runtime. We used to be called Metro and it is now called Windows Runtime, but it requires, I think, at least several person-market work to get to some usable stage, and so far nobody has had time to do it. Because again, that was rigid. No school opens those projects, so nobody's paid to work on this, so you have time to do something you do, but it's difficult to have six months of your time to spend on WX.

I have started working on WX Widgets when I was a student. So basically only students have so many. And we are not. None of us are students anymore, unfortunately. Do you want to tell us a little bit more about how you first got involved in WX Widgets?

Yeah, it was actually pretty simple. I just wanted to write a program. I had a modem, which used some proprietary crack software that was required to work with this. And I was using Linux, of course, and for the proprietary software was Windows only. And so I wanted to write a program to work with this modem, which would work on Linux. But as long as it worked on Linux, I wanted it to work on Linux too. So I started looking for some library that would allow me to do that. Qt back then was closed source and pretty expensive.

Much too expensive for a student back then. So it wasn't really an option. There were a couple of other options which I explored. But finally I chose WPGITS because, and it wasn't really an option. There were a couple of other options which I explored, but finally I chose W3GITS because of its excellent documentation. Excellent compared to other open source projects. So I really appreciate that it had documentation because that was a rarity back then. I don't think it changed that much since then. So I started working with W3GITS and of course I quickly found that a lot of things could be improved. And so I started submitting patches, sending them to the

mailing list, because we didn't have Git back then. And somehow I got pulled in, and finally I have never written an application for this modem. But I did improve public switches. That was back in 1996 or thereabouts.

Oh, wow. Are there any particular areas of WXWidgets that you've made a significant amount of contributions? Or have you kind of worked all over the whole library? Well, I guess I'm officially considered, as much as there is an official, not an official in WXWidgets, but I am semi-officially maintainer of the Windows core and basically everything that is low-level OS specific, but not necessarily new specific stuff. So basically there are other developers who maintain Mac and GTK ports and I try to take care of most of their things. But to be honest, I spend much less time on the Blitzkrieg nowadays because there are

just too many other things to do. And there are other people who still... We get used to these things all the time, so that's great. I don't know where they come from, but people just view and start making good prices and continue making good prices. It's very easy to conclude that. I think that we really try to do our best to barrier the answer as much as possible. We do have our standards.

So basically, you submit a new feature, you have to submit documentation, for instance. And if you can submit some tests, that's very much appreciated. But basically, if you make a good patch, you can be pretty sure

that it's going to be accepted. I think it may be different from other more corporate-backed open-source projects. So we really try to keep the spirit of pioneersed open-source projects. We really try to keep the spirit of pioneers of open-source. Along those lines of

development and accepting contributions from other people, is WXWidgets evolving as C++ evolves? What version of C++ do I need? What compiler do I need to compile with right now? It evolves but it evolves flash-to-listen. Like, what version of C++ do I need? What compiler do I need to compile with it right now? Evolve, C++, because again, it turns out that not so many people are really motivated in just writing the code for the writer's name.

So W3 just still uses compiles using C++98. Okay. All files in C++, C++11, 14++14, C++17, I could regularly fix warnings or errors, errors are rare, warnings are frequent, if they arise during the compilation of the library. But the focus is not really on making the library itself use more than C++. The focus is making the applications using more than C++ work well with the library. And so since many years, for example, we support using Lambda as an event handler in the library. So this doesn't actually require using any C++ 11 inside the library itself, but we do allow to do this if your application is C++ 11. And using Lambda as an event handler is really the light thing. So for me, C++11 really changed a lot of things. And it was really great to use.

Also for some historical reasons that nobody cares about any longer, but back when WSWidgets was found in 1992, C++ was really C with classes and not C with two faves. And you couldn't really count on having standard library implementation. Many of the platforms that were supported by WSWidgets. So historically, WSWidgets used its own string, container classes, well, you know, all that stuff. And this hasn't fully changed yet, even though since 20 years you can compile WSWidgets using standard library classes instead, if you want. But the thing that matters is that you can use standard library classes in your

application. WSWidgets does its best to transparently interoperate with them. So you can pass std string to WSWidgets even if internally it uses its own WX string. And you can fill some combo box with the elements of std vector even if internally it serves in some bespoke WX. So again, when people look at the WX3 distortion, they may sometimes be horrified by all this amount of slush. But actually, it's not that bad. And yes, we probably will get rid of them one of these days.

But actually, what counts is that your application can use the latest C++ features, and my own applications do so. Again, I'm motivated creative than this because I use it myself. And so your application can use normal C++ and later C++ features, and it works well with WXWidgets.

So our focus is on that. Okay. Makes sense. Definitely makes sense. Do you have anything on the roadmap for WXWidgets? How often do you release new versions, and is there anything you're planning in the future to add to it?

That's a thing for me. WXWidgets is notorious for releases. Well, I guess I should maybe say that I'm notorious for things, because I'm making the releases, and I'm a perfectionist, so I hate

leaving things not working badly in the release. I try to do this one basically business that can be no releases for years and years, which is not ideal either. So right now the focus is on 3.2 release, and the main feature is finishing high DPI display support, which is already not too bad in Geek Master, but there are still things remaining to do. And we basically just need to finish and make this release. That's right now.

We hope to make it this year. To be completely honest, we hope to make it last year as well. Okay. But this year is for real. Okay. Jason, do you have any other questions? No, I don't think so. Okay. Vadim, is there anything else you wanted to go over before we let you go?

No, it was nice talking to you guys, and thanks for inviting me once again, and your podcast and and going to resume my work from wx which is 3.2 released thanks for coming on i guess one more question i have sorry i know we just did that but i guess one more question would be um if you're just getting started in wx widgets you want to make a new GUI application, what's that process look like? Basically, I'm a believer in example-based

learning. So what I would do is just take our Hello World example and basically compile it, change it, build it successfully, and then just start hacking on it and modifying it to add the things that you need. So WX widgets a decent documentation,

but what is great about it is that it has almost hundreds of examples. So, in the samples directory, there are a lot of examples that, and basically, if you want to know how to use some particular API element, be it a class or a function, you just can grab the samples sub directory and find an example showing how to use it. And so this is how I operate. And I was surprised that not all people are trying to do it like this, but I've tried to go from examples again, and I think that W2D is great if you work like this. If not, well, there is documentation which is not always perfect perfect. There are all the usual community support channels like forums, IRC, mailing lists,

Stack Overflow. There are quite a few WX widgets, so if you type your question, ask Stack Overflow WX widgets, chances are I will see them. I'll try to answer the questions there. Awesome. Okay, sounds good. Thanks, Vadim. Thanks again.

Thank you. Bye. Bye. Thanks so much for listening in as we chat about C++. We'd love to hear what you think of the podcast. Please let us know if we're discussing the stuff you're interested in, or if you have a suggestion for a topic, we'd love to hear about that too. You can email all your thoughts to feedback at cppcast.com.

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