The last week we once again run into an issue with the Linux shared library loader. In a Xojo app you may end up having several libraries several times in different versions. For example the system provides the zlib library in some version, e.g. 1.2.3 on an older Linux installation. The MBS Compression Plugin uses zlib in version 1.2.8 while DynaPDF uses a custom patched 1.2.7 for the PDF compression. Also the Xojo runtime may come with its own version.
Now it seems like there can be a problem. All those versions of the library may or may not export publicly their functions and you may have several deflateInit functions around. Now when resolving the functions references in a shared library (e.g. plugin), the loader will pick one by name to solve it. And for us this was catastrophic a few times. Because you end up getting a different version of the library than expected. DynaPDF brings 1.2.7, but may end up getting tied up to 1.2.3 or 1.2.8. For PNG, JPEG, zlib and other libraries, there are checks in place to make sure the header files and the library matches in version. If versions won’t match data structures may have different sizes or parameters to functions have different meanings.
In DynaPDF the resulting error from a different zlib version is:
This is solved for MBS Plugin 17.3pr4 by setting all non-exported symbols to local symbols. This should make all functions to resolve within the library take precedence over functions from other libraries.
For DynaPDF we added GetPNGVersion, GetJPEGVersion, GetTIFFVersion and GetZlibVersion functions. They allow you to query the jpeg, png, tiff and zlib versions used in the DynaPDF library.
PS: For FileMaker Cloud we do the same fix next prerelease.
As I stay a few extra days in Phoenix, we will have two Xojo developer meetings:
22nd July 2017 in a restaurant near Phoenix.
28th July 2017 in a restaurant near Tucson.
I know I have over 20 Xojo developers using my plugins in Phoenix alone.
If you like to join, please contact me soon.
I reserve a table in a nice restaurant and I will be there. You can join and we can shop talk all night. Ask me plugin questions, bring your laptop and show projects.
And of course we discuss latest changes in Xojo, upcoming conferences and what's new in plugins.
Thanks to the 64-bit debugger in Xojo 2017, we can now easily try 64-bit applications and that's a must as Apple's latest frameworks don't support 32-bit anymore.
So yesterday and today I worked on a test project including a Xojo plugin for CoreML framework. Here is my test project running:
While macOS 10.13 is not ready for a few months, we can already download the beta versions of macOS and Xcode and play with it. You can use a model quite easy as you see in the Core ML presentation from WWDC 2017. With just a few lines of code we load a model, setup source image and run it though the neural network to classify the picture. You can get sample models from Apple's Machine Learning website.
The plugin will be available later this year with the macOS release.
Now the are a lot of new APIs, but I'd like to know from you what you'd like to see in our plugins for Xojo and FileMaker.
Usually we provide lower level wrapper for Xojo to Apple's APIs for macOS with hiding all the threading issues from you and translating values from native Xojo types to the matching Foundation types. As there is currently no iOS plugin SDK for Xojo, we can't make all features available via declares.
For FileMaker we usually provide a much more higher level API to do selected things and provide plugin functions for both macOS and iOS.
If you have ideas and wishes, please email me. I'll keep a list and if we have a lot of wishes for a given API, I may give it some priority.
We are looking for talented and passionate speakers to present at XDC 2018 in Denver, CO! In addition to the fame, becoming an XDC speaker gets you a 50% discount on conference registration!
If you are interested in presenting, please submit a proposal with your session topic(s) and brief description(s) (3-5 sentences), along with your full name and contact info (preferred email and phone number), to the XDC Conference Coordinator at email@example.com. If you are interested in presenting, but not sure of a topic, please reach out to us and we can help you develop your session. The deadline to submit proposals is Friday, June 30, 2017.
Here are some tips on submitting a good session topic.
Still 20 days left to submit a proposal. Myself I can of course talk about what's new in MBS Plugins, or take about making plugins or maybe make a session about comparing what machine code the compiler creates with various options and Xojo versions.
Improved key length handling for CipherMBS class. Init functions now report true on success and false on failure. Short keys are filled with zeros (as before), we report false in case of errors, but still may take reduced key (as before).
Updated SQLite to 3.19.3.
Fixed bug with DynaPDFMBS.ShowDifference and rotated pages.
On my next visit to Nuremberg, I'd love to make another developer meeting:
Wer hat Interesse an einem FileMaker & Xojo Entwicklertreffen im Juni in Nürnberg?
Einfach gemütlich zusammen sitzen und über Xojo und FileMaker Neuigkeiten, Konferenzen und die täglichen Probleme bei der Softwareentwicklung unterhalten.
Gerne zeige ich auch neue Pluginfunktionen oder helfe bei Problemen mit Projekten. Einfach Computer mitbringen und was zeigen.
Wir treffen uns am 16. Juni 2018 in einem Biergarten in Nürnberg.
Bei Interesse bitte bei mir melden.
We will have a great conference in the Maritim Hotel near the main station can offer us 50+ rooms as well as one or two conference rooms. If we have a lot of speakers and attendees, we could go two track!
We have blocked 100 rooms and offer an 122 Euro rate for the nights from 5th to 8th September including pool, breakfast and Wifi.
Nearby other hotels in the area offer rooms for less, down to 60 Euro/night.
Walking distance to center of city is just a few hundred meters. So you can walk to Hofbräuhaus, city hall and the famous historic buildings like palace Nymphenburg. And if you like to take a drive in the countryside, you are quickly down to the alps. e.g. take the train up on Wendelstein for a great view.
5th September 2018: Training Day in English for beginners and advanced
6th September 2018: First Conference Day
7th September 2018: Second Conference Day
8th September 2018: Training Day in German for beginners and advanced
We look forward the conference and plan to have get togethers on all evenings for having dinner together.
For the rest of the year, we look for attendees and speakers to sign up. If you have a good idea for a session in English, please send us your proposal.
If you are near Austin or plan on coming to Austin - join the Austin-based Xojo team for lunch in July to talk Xojo and get to know other users in and around Texas! If you are interested in joining us - please reply to this survey so we can find the best date!
Today I had an interesting request for a task monitor written in Xojo to see how much CPU some processes need and to report when they are stuck (no CPU usage over longer time pointing to deadlock) or run at 100% for a long time. And of course to see if they go away due to crashes.