Im currently working on a Swift Framework using OpenCV (3.4.3), and im having some troubles or getting confused about how the build processes work.
Note I'm not using CocoaPods, Im using the framework file/folder provided by OpenCV
So my problem is that I'm creating the swift framework that depends on OpenCV, once I've built my framework and add/link it to a App (Its added to the embedded frameworks section), the app runs fine with no errors. This is where my confusion lies, I would expect to also add OpenCV to my app then have them link at runtime/compile time, but that's not the case OpenCV is magically linked and working. I have also double, triple checked that there is no references of OpenCV in the app to ensure its not getting pulled in anywhere.
For some sanity checks I created a basic framework called TestFramework, which had 1 class, with a static function just so I can test the above process. I added TestFramework to the main framework im working on, and built it. I then added that Framework to my app, and it would not build because the TestFramework was not present in the App as a dependency. Then adding the framework allowed it to build, and the main framework then was able to call the code within the TestFramework.
There seems to be some discrepancy between how the two work, unless the OpenCV framework is built in a different way allowing it to work without the app depending on it.
Any help or thoughts would be great, thanks.
I absolutely can not understand how it works. I started with a simple one: created framework using "Cocoa Touch Framework" template and add some code to source files. Then using cocoapods I installed some pods to this framework-project. All looks good (maybe not so good actually) and build fine. After that there was an attempt to connect my framework to other xcode project. I did this as follows: just took my test.framework file from Product folder and transferred to another project. At first everything was not bad. The import was successful and I can use my framework-code in another project. But when I run it I have error: dyld: Library not loaded: Reason: image not found. I tried all of the answers to this problem, but nothing helped me.
After that, it was decided to try to connect my framework to other project. This time I got a completely different behavior: namely, I was able to connect the framework, but I could not access the code inside it. I'm completely confused, because I did not change anything. I just did the same with another project.
Please help me. What am I doing wrong?
A related questions:
Can I connect the framework just moving test.framework file into
another project?
For some reason, I should use the approach described above, is there a chance in the theory of success or all that I have done before is not correct?
I tried it a lot with the same result you get , until I posted the problem in Apple forums and they respond with Nested frameworks are not supported in IOS
I have 2 frameworks created by me that use (both of them) a library also created by me.
The first framework initialize the library and makes all its workflow. After finishing the first framework, the second one must start.
But when the second one is going to start, after initializing the library, the app using both frameworks crashes with a exc_bad_access error.
Apparently the library is created correctly, but if i comment the line of code to initialize the library in the second framework, the workflow continues (it crashes later because it has no library initialization).
Is there anything I'm doing wrong? Should I use two separate libraries instead?
EDIT:
Imagine the situation:
Framework A has this methods: start, stop. And while it works it delegate to the methods: infoFromA,frameworkAFinished.
Framework B has this methods: start, stop. And while it works it delegate to the methods: infoFromB,frameworkBFinished.
Both start methods initialize the static library mentioned (lets call it problematicLibrary).
Both frameworks present some views to make its functionality. So lets make an example of the app workflow.
At the app view viewWillAppear method, I start the Framework A just using:
[FrameworkA start]; , this will initialize the library and present a view. With this view (using my problematicLibrary) some info will be delegated to the infoFromA delegated method. And after all the info is delegated, it will delegate to frameworkAFinished.
When the FrameworkA has delegated to the frameworkAFinished I start the next Framework: [FrameworkB start]. As the other Framework, it will initialize the library and present a view. While debugging, all the initialization of the library is done (create the instances of the needed objects and a new instance of the library is created) and while its presenting the view it goes through the viewDidLoad method and then it throws an exc_bad_access error at the problematicLibrary initialization line (which has been done before and continued to present the view!!) without going into any other method from the view.
I have checked if the initialization is doing well, and all the variables were at null value before the initialization, and a new memory address is given to the library object.
This sounds strongly like a symbol conflict to me. I'm just surprised the linker didn't catch it, but I assume that's because you're using a static library in both your frameworks instead of simply yet another framework.
Generally speaking, I'd warn that "this is a bad idea™". What you're trying to introduce into your design is basically dependency management. Like a lot of blog articles and specifically this SO answer suggest, you should avoid packaging frameworks (and by extension libraries) into frameworks.
What most likely happens in your scenario is this (I admit I'm guessing a bit here): You linked the library into Framework A. Thus, the library becomes a fixed part of it. Its symbols are in it, even if you did not expose them to the app in any header files or the like. As long as you use only that, everything works smoothly. Then comes Framework B, of which the library is also a fixed part. Even though you can't see it from your app, the very same symbols are inside it. This, however, clashes with the symbols that were already loaded by Framework A, hence a crash (as said, this would usually be caught by the linker, but I guess you "tricked" it by building the frameworks beforehand and packaged the library in them). Maybe somebody else can explain this in more detail, but that quickly becomes besides the point as to how you would go for a solution. From how I see it, it just won't work this way.
So here's a suggestion for how you can solve your problem:
If you really, really need to split like this (two frameworks used in your app using the same dependency), I'd suggest removing the library from the frameworks (i.e. make them depend on it, but not package the actual .a file in them) and documenting that properly. Then add the library to your app project, just like you added the frameworks.
If you want to make this fancy and easily installable into other apps, I'd recommend setting up a private CocoaPods repository and turn your frameworks into private pods. You can then easily define the library (or rather "new Framework C") as a dependency for Framework A and Framework B. When you then pod install in your app, cocoapods figures out the dependency and adds Framework C automatically to your project. This scenario is exactly what cocoapods (or any dependency manager for that matter) was designed for. It automates and helps in the project setup, so that the final build (the app) doesn't have to figure out dynamically what it can and can't use. The end result is the same.
Trying to duplicate that "in code" quickly becomes messy. Frameworks trying to figure out things of the surrounding app/project that uses them (like "is my dependency so-and-so already linked? if not, can I load my own version of the library?") can lead to a lot of pain.
Okay, in response to your comment I'll try my hand at a more detailed How-To for the non-cocoapods setup. As a preface, though, let me say that that's kinda hard to do on top of my head, as I have no ready sample project to toy around with. Since this is one of those "set it up once and then forget aout it for a long time" I have to admit my recollection of these things is a bit fuzzy, so consider this as a sort of "rough direction". There might be things you need to configure differently than how I recall them. Other SO user are thus hereby invited to edit and correct my answer here, too. :)
First, I have to say I am not exactly sure whether you need to convert your static library into a framework or not for this, I think you don't so I'll go from here (I have never used a static library in that way).
That means you can leave the project that builds your library as is. On second thought, you probably have to do this to be able to link against the library without making it a part of the framework that uses it. I will still refer to this code as "library" in the below points, but assume that you're able to turn it into a dynamic framework as well.
The projects building Framework A and Framework B should be changed. I don't know how you have this set up (as one project with various targets, whether you have a "development application" as part of it to test the frameworks on themselves, etc.), but the important thing is that in the target that builds a framework, the library should be linked (i.e. in the "Link Binary With Libraries" build phase), but not copied (i.e. it must not be in the "Copy Bundle Ressources" build phase). It might be tricky to set up any development/test target you use to run, depending on how you did that so far. For example you might have to manually edit Library Search paths in your build settings to be able to properly compile the framework.
Lastly, you need to change your final app's project settings, obviously. The library that was originally part of Framework A and B now needs to be linked to from its project directly, and, obviously, it needs to be copied into the bundle as well. Note that any projects that include either of your frameworks (A or B or both) in the future must do so, otherwise they won't work, because these frameworks expect the library to be present (but no longer "bring it with them").
In spite of this long-ish text wall, it shouldn't be that complicated, I think, but you may still want to check out how cocoapods can support you with something like this, perhaps it's helpful in the future. The linked article expects basic knowledge on how to use a pod and write one, but the other guides on the site explain that pretty well. I am just saying this because in the end, when using cocoapods in a project to add multiple libraries/frameworks that introduce dependencies, it basically sets up your project in the way I described above. It uses some fancy shell scripts that ensure everything is copied to the correct folders and such, but overall speaking that's how it works: A pod's podspec tells cocoapods what additional pods to include in your app for it to work (a dependecy the pod expects to be there, but doesn't "bring in" by itself).
Check if they are both compiling for the same target.
Check if they have access to the same target membership.
Check build phases to see that they are both there.
I think because the first library is not 'well' referencing the second one.
Also i think that you can't import a framework inside another one.
To make things easier, you can merge the two frameworks on a single one.
Also you can add a callback (using protocols or closures) that informs for the end of the first workflow, and you use this callback to initialize the second framework. This way the initialization will not be made automatically.
I'm building an iOS framework where only a single header file is exposed, and the rest of the code is private. Within Xcode I have all objective-c exception breakpoints on, so normally when there's an exception I'm brought to where it occurred in the code.
During testing in a totally new project that is using this framework I created, every now and then when an exception is raised inside the framework, I'm brought to the otherwise private framework code, which is obviously not what I want.
I think this may be because the actual raw framework code/project exists in my environment and wouldn't occur for another person using my framework without access to the actual files, but unfortunately I don't have any way to currently test this theory. Does anyone know if this is something I need to be handling in order to truly keep the project files private that I intent to, or is this just a function of having the code exist locally?
I was able to get in another dev environment with a fresh project to drop in the framework and force an internal framework crash and it appears that if the otherwise private framework files exist on the same environment and a crash occurs when you have objective-c exception breakpoints enabled it will open the private framework file in question, BUT if you don't have those private framework files (which consumers of your framework wouldn't) you will simply be taken to the normal crash/stack trace view like below:
I have two projects in an F# solution.
1. main project with [EntryPoint] and set as the StarUp project.
2. support, the second project, holds a group of support modules. I.e. they are only called and never initiate anything nor serve as the entry point nor are the StartUp project.
For the last module in the support project, compiling in Visual Studio gives
warning FS0988: Main module of program is empty; nothing will happen
when it is run
While using compiler option nowarn inline as #nowarn "988" in the module causing the warning does suppress the message I would rather add something like a dummy function with comments that resolves the issue.
How does one make such a dummy function to resolve the warning?
EDIT
Jack is correct in that my support project was setup as a Console Application instead of a Class Library. Changing to Class Library resolved the warning. It is also nice to know about do () for the other case.
EDIT
While it seemed odd that I would have set a support project as a Console Application, I recently found that for some reason when I made a change to the code in the project, something changed the Output type from Class Library to Console Application. I suspect it has to do with the F# PowerPack and it's build rules, but it's only a guess.
Are you building the support project as a Library or as a Console Application? (This is set via the project properties page.)
If you're building it as a library, then you may need to add a do() at the end of the last file in the project. This is necessary to make the F# compiler happy in a few specific scenarios, like when you create a module which contains only assembly-level attributes (because they're applied to the assembly, the module appears "empty" to the compiler).
You can see an example in my code here:
https://github.com/jack-pappas/FSharp.Compatibility/blob/master/FSharp.Compatibility.OCaml/AssemblyInfo.fs