I'm currently trying to load a plugin assembly dynamically in a monotouch app.
To do this, I'm referencing the plugin dll in my app project, setting the limker to 'sdk only' and then i'm trying to call Assembly.Load(filename) within my app when the plugin is required.
This is the same approach that I've previously successfully used in monodroid. However currently, this is failing in monotouch with a FileLoadException.
Is this approach possible in monotouch? Is there a special file path you need to include? Or is this not supported in the aot environment?
Note: Obviously there are other ways I can achieve a similar effect - and I do have a backup plan... but this is my preferred route (if I can make it work)
Code like:
var a = Assembly.Load ("mscorlib.dll");
Assert.NotNull (a);
works fine with both the simulator and devices. However the parameter for Load is assemblyString which is not a filename (even if the exception thrown make you think it is).
Many other overloads exists (for Load) and other methods too (e.g. LoadFrom) but they might not all work inside MonoTouch (since some runtime support might be missing).
NOTE
Handling of mscorlib.dll is special (and works in more cases than other assembles, i.e. shortcuts). However the reflection-based methods seems to work as expected in more cases, e.g.:
string filename = System.IO.Path.GetFileName (GetType ().Assembly.Location);
Assembly assembly = Assembly.ReflectionOnlyLoadFrom (filename);
Assembly.Load (or any other way of loading code dynamically) is not supported in MonoTouch.
This is an iOS restriction - all the executable code has to be in the app (and it has to be native code, which is why we use AOT to generate native code at compile time).
Related
The title says it all. But, are there too many files to be replaced and is there a risk? What I mean is, there are files like d3d11.dll. Could I replace the files with with something like d3d12.dll or something like that?
When code is compiled it uses 'headers' and usually links to 'libraries' which refer to functions inside the dll. When the game loads it maps the DLL into the address space of the executable so that the program can use features in the DLL.
So if the Game does D3D11_DrawTriangles, it will end up calling that feature in d3d11.dll. Dropping in the DX12 DLL won't work because the expected function is no longer there (and besides, the executable would still be looking for the 11 DLL - it wouldn't even load).
Upgrading from DX11 to DX12 is a major undertaking; the graphics APIs are very different.
Put another way: It's like someone dropped a Fiat engine into your Volvo. Would it work? How much effort would it be to rewire all the pipes and electronics to make it work?
I have a project that is running fine on Android and WinPhone 8. When I attempt to run on iOS, I've getting the following error
Microsoft.Practices.ServiceLocation.ActivationException: Cannot
register: No public constructor found in x
where x is whatever SimpleIoc.Default.Register<T, TU>(); the flow hits first. I've moved the code around (as suggested elsewhere) to ensure all of the platform specific SimpleIoc calls are made in ViewModelLocator.
I've added public default ctors in the classes that are complaining about the error (I have though set the PreferredConstructor to the original, not the newly added public ctor).
I have a feeling that this error is a false positive (something else is failing, but pointing at that code).
Using Xam.iOS via a build server (the code is coming from VS2015). Xcode is running the 8.3 emulators (it may need updating to allow for 8.4 testing)
It could be that the Linker is optimising away the constructor, if it thinks it's not used. Try setting the Linker Options to "Don't Link" and see if it does it again, or even new-up an instance of the class elsewhere so that the Linker knows that the constructor is used. You don't necessarily want to leave it that way, but if it eliminates the error, you'll at least know the reason.
The [Preserve] attribute did the trick for me.
Decorate constructor with it and keep your linker settings.
This attribute is part of the Microsoft.WindowsAzure.MobileServices namespace.
dllmain.cpp(16): warning C4447: 'main' signature found without threading mode
l. Consider using 'int main(Platform::Array<Platform::String^>^ args)'.
Above is a warning I got from building a Windows Store App DLL project. I didn't change anything in that default dllmain.cpp file except for including my own version of pch.
The documentation for this warning (along with many VS2012 errors/warnings) is nowhere to be found on MSDN and here is the only relevant link I can find:
http://social.msdn.microsoft.com/Forums/en-US/vssetup/thread/6daa9587-fe54-4e84-a8b9-0e5c52c2f6e8/
and the op there didn't get an answer.
If anyone knows what it means and how to fix it, it would be great!
As far as I can tell, you can safely ignore the warning. The compiler cribs when it sees a Win32-style DllMain being compiled using the /ZW flag (Consume Windows Runtime Extensions). However, the function gets called as you'd normally expect.
Alternatively, you can work around the warning by compiling dllmain.cpp without /ZW. You might need to adjust the PCH settings for this to properly work. This is the path taken by the DLL (Windows Store apps) C++/CX project template in Visual Studio.
Incidentally, the reason you do not get the warning when you're trying to build a Windows Runtime Component project (which builds everything using /ZW) is that a Windows Runtime Component doesn't declare a DllMain. This is not to say that it can't; it just picks up the dummy DllMain that the CRT defines (which basically turns off per-thread initialization and reports success).
I have built a linux shared object which I inject into a 3rd party program to intercept some dynamic function calls using LD_PRELOAD.
The 3rd party program uses a SO "libabc.so" located at some path. My injected SO uses another SO, also called "libabc.so" located at another path (essentially identical but slight code differences).
My problem is now, that calls to a function "def" which appear in both libabc.so are always resolved by the first. (Presumably because it is loaded first?!) How can I get them to be resolved with the second libabc.so?
Many thanks!
Unless something changed since I used to do this, you will need to dlopen() the library you want to pass calls on to and call the function manually, something like;
handle = dlopen("/path/to/libabc.so", RTLD_LAZY);
otherDef = dlsym(handle, "def");
orderDef(parameter);
There is a complete example how to do this very thing at LinuxJournal.
If you only want to use one libabc.so version, you can always use LD_PRELOAD to load it along with your own shared object before anything else.
If you want to use multiple versions, you have a few alternatives:
Use dlopen() in your shared object to load that library. Since you have created a function injection object you should be familiar with this procedure. This is the more generic and powerful way - you could even mix & match functions from different library versions.
Use a different DT_SONAME for the library version your shared object links against. Unfortunately this requires (slightly) changing the build system of that library and recompiling.
Link your shared object statically against the library in question. Not always possible but it does not require modifying the library in question. The main issue with this alternative is that any change in the library should be followed by a relinking of your shared object for the changes to be pulled in.
Warning: you may need to use a custom linker script or specific linker options to avoid symbol conflicts.
I am trying to build an old version of an application which consists of VC++ projects that were written in Visual Studio 2003.
My OS is Windows 7 Enterprise (64-bit).
When I try and build the solution I get the following errors:
error C4772: #import referenced a type from a missing type library; '__missing_type__' used as a placeholder
fatal error C1084: Cannot read type library file: 'Smegui.tlb': Error loading type library/DLL.
They both complain about the following import statement:
#import "Smegui.tlb" no_implementation
This is not a case of the file path being incorrect as renaming the Smegui.tlb file causes the compiler to throw another error saying it cannot find the library.
Smegui is from another application that this one depends on. I thought perhaps I was missing a dll but there is no such thing as Smegui.dll.
All I know about .tlb files is that they are a type library and you can create them from an assembly using tlbexp.exe or regasm.exe (the later also registers the assembly with COM)
There is also an Apache Ant build script which uses a custom task to invoke devenv.com to build the projects. This is the same script that the build server originally used to build the application. It gives me the same errors when I try and run it.
The strangest thing about this is that I knew it ought to work seeing as it is all freshly checked out from subversion. I tried many different combinations of admin vs user elevation, VS vs Ant build, cleaning, release.
I have got it to build successfully about 5 times but the build seems to be non-deterministic.
If anyone can shed some light on how this tlb stuff even works or what this error might mean I would greatly appreciate it.
I found a far more reliable solution: open the tlb with oleview.exe and then close it.
Not sure what this actually does but it works every time.
I think oleview is actually one of the samples included with Visual Studio but I haven't had the time to debug it and see what it is doing.
I ran into this error because one type library was trying to load a dependent type library, which it could not find. Even though the dependent type library was in the same directory, and even though that directory was in the searchable path, the compiler would error loading the first type library, but not mention the dependent type library in the error.
To find the pseudo-missing type library, I ran Process Monitor (procman64.exe) during the compile. This showed that after the reported type library had successfully loaded, a dependent type library could not be found. It even showed all of the places that it was looking for the dependent type library, none of which were where it should have been looking (e.g.: ).
The fix was to add a <PreBuildEvent> to the project to copy the dependent .tlb file to one of the directories that was actually being searched.
<PreBuildEvent>
<Command>copy /Y ..\Lib\Interop\CWSpeechRecLib.tlb .\</Command>
</PreBuildEvent>
http://msdn.microsoft.com/en-us/library/sce74ah7%28VS.71%29.aspx
smegui.tlb is referencing some other tlb that the compiler can't find. If you have the .idl for smegui you might be able to figure out what the other is. I suspect the missing tlb is something that original build machine had registered but that your machine doesn't have registered.
A type library is a binary description of a set of interfaces, coclasses and enums. They're usually generated for COM components, in the case of tlbexp and regasm the tlb is created from the assembly metadata. For native COM components they are usually generated from an idl (Interface Description Language) file by the midl tool.
Edit:
I just noticed you're on x64 Windows. Are you building the project with a new version of Visual Studio? If so, are you targeting x86 or x64? If the latter, it may simply be a 32bit component that the compiler can't find (or less likely, a x64 component the x86 compiler can't find if you are targeting x86), for WOW64 the registry is virtualized for x86 vs. x64 applications.
Well I finally found out why I managed to get it to build sometimes and not others... sort of.
So long as I ran the build script with elevated administrator permissions and let that get as far as it could until that error occurred, then run the build script again as a protected administrator succeeded. Those steps must be done in that exact order with no other steps in between. If I try build in Visual Studio it does not work (although I did get it to succeed once). Probably some kind of virtualisation issue although it still doesn't quite make sense.
Well I don't need help on this any more and I know it's probably impossible to fully answer this question without knowing exactly what the build is doing. However if anyone does have any more thoughts I would happily receive them.
Cheers,
Steiny