The situation is as follows:
Let's say I have a project with 2 nuget library references - lib A and B:
A is at version 1.5
but B references an older version of A, e.g. 1.4
In VS, everything can compile and run properly (I guess because A 1.5 implements all the functionality that 1.4 required).
But running in the Azure emulator resulted in an immediate TypeLoadException, presumably because the older version of A was loaded (I think its because B was loaded first, and its dependency was A 1.4), thus the types and methods (e.g. MyObject) added in A 1.5 and used by my project are not recognized.
Exactly what I get is:
"Could not load type 'MyObject' from assembly 'A, Version=1.4, Culture=neutral, PublicKeyToken=null'."
I've substituted the real names and version numbers with A and 1.4 of course :)
I know that one solution would be to update B to use A 1.5, but is there any other way to fix this? In case there are other libs B, C, D, E... that use A 1.4, I would have update the reference to A in all of them...
Thanks for any help
Either upgrade your projects to use the latest NuGet package or try adding a binding redirect to your app.config to map assembly references to the higher version.
Related
I try to develop a thirdparty unixODBC driver, it is a secondary development based on the original file libodbc.so.2.0.0.
so I want to rename 'libodbc.so.2.0.0' to 'libodbc.so.2.0.0_renamed'. And soft link my dynamic library file to libodbc.so.2.0.0.
But I found an issue bothering me, when I rename native file and run 'sudo ldconfig', the file named 'libodbc.so.2' automatically linked to the renamed file 'libodbc.so.2.0.0_renamed', as below:
I could not understand that:
why it occurs;
how to appropriately replace the library.
I don't have enough ackownledge about linux, so that I failed to get any keyword to search and deal with it.
Could you help me, thank you very much!
Shared objects under GNU/Linux follow a specific version naming scheme, which is known by the loader (and OS component, actually part of libc framework) to determine if a newer library is retro-compatible with some older version to which a binary was originally linked against. By adding the renamed suffix, you are violating the convention and the dynamic linking system is getting confused. You should renamed as suggested by #Bodo above.
In addition, perhaps rather than using rename, you might consider using the very versioning scheme. From GNU Build System (aka Autotools) manual, the version cheme is like it follows:
Versioning: CURRENT:REVISION:AGE
CURRENT The latest interface implemented.
REVISION The implementation number of CURRENT (read: number of bugs fixed...)
AGE The number of interfaces implemented, minus one.
The library supports all interfaces between CURRENT − AGE and CURRENT.
If you have
not changed the interface (bug fixes) CURRENT : REVISION+1 : AGE
augmented the interface (new functions) CURRENT+1 : 0 : AGE+1
broken old interface (e.g. removed functions) CURRENT+1 : 0 : 0
Therefore a possible history of your lib might be:
1:0:0 start
1:1:0 bug fix
1:2:0 bug fix
2:0:1 new function
2:1:1 bug fix
2:2:1 bug fix
3:0:0 broke api
3:1:0 bug fix
4:1:1 bug fix
5:0:0 broke api
You might, for instance, call the older and newer versions of libodbc.so.x.y.z, according to your needs. Just an idea.
As far as I understand, "2" in "/lib/ld-linux.so.2" changes very rarely. There are old programs that can't work with new library and new programs that can't work with the old library. But they both refer to /lib/ld-linux.so.2, preventing installing both libraries.
BTW what are that version 'GLIBC_2.17' not found things? Why version is not in soname, but somewhere else?
Whenever a library is changed in a way that old programs do not work with the new version of the library this number is chaned. If old programs will still work with the newer library (and programs needing the new version will not cause a crash with the old library) there is no need to change the number because you can simply install the latest version of the library.
As far as I understand the "2" (it was "1" ten years ago) should not change any longer. The reason is simple:
The first version of "ld-linux.so.2" was written in a way that any version of "ld-linux.so.2" should work with any program using this file - maybe printing an error message when an older version of "ld-linux.so.2" is used.
This means: It is never necessary to install two different "ld-linux.so.2" files but it is enough to install the latest version of this file. You should not simply overwrite this file because it comes as a bundle with other files (e.g. "libc.so.6") that must have the same version.
In the "2" version of the loader .so files may contain a table of version numbers supported. So "libc.so.6", version GLIBC_2.16, may contain the information that "GLIBC_2.15" is also supported by this version of the library. (New versions should be backward compatible so this should be the case.)
Programs may contain a list of versions required (for example: a program requires libc.so.6 version "GLIBC_2.17"). The loader (ld-linux.so.2) checks if the library supports the version that is required by the program and refuses starting the program if not. In this case the error message form your question is printed by the loader.
According to MSDN, there is version attribute but if you specify a wrong version number VC still compiles the code. For example:
// MSO.DLL (Microsoft Office, Object Library)
// Office 10.0 => version(2.2)
// Office 11.0 => version(2.3)
// Office 12.0 => version(2.4)
#import "libid:2DF8D04C-5BFA-101B-BDE5-00AA0044DE52" version(123.456) //< wrong version.
How to force the compiler to fail on such code? I would like to use only specific version of type-library.
You can't. The rules are explained in LoadRegTypeLib:
LoadRegTypeLib compares the requested version numbers against those
found in the system registry, and takes one of the following actions:
If one of the registered libraries exactly matches both the
requested major and minor version numbers, then that type library is
loaded.
If one or more registered type libraries exactly match the
requested major version number, and has a greater minor version number
than that requested, the one with the greatest minor version number is
loaded.
If none of the registered type libraries exactly match the
requested major version number (or if none of those that do exactly
match the major version number also have a minor version number
greater than or equal to the requested minor version number), then
LoadRegTypeLib returns an error.
Your case matches the 2nd bullet, not the 3rd. Microsoft does spend a lot of effort on making these type libraries backward compatible. Not taking advantage of it is easy to do. Build your project on a machine with the right type library. Copy the generated .tlh and .tli files to your project directory and check them in. Replace the #import with #includes for those files.
I am using MonoDevelop 2.2 from the Debian testing repository. I have installed the addins for GTK support, for version 2.8 and 2.10.
When I compile my solution, I get warnings saying Warning: Assembly 'glade-sharp, Version=2.10.0.0, Culture=neutral, PublicKeyToken=35e10195dab3c99f' not found. Make sure that the assembly exists in disk. If the reference is required to build the project you may get compilation errors. (ProCos)
The warning is perfectly alright, because the installed libraries do not offer V2.10 of glade-sharp. So I open the reference dialog, remove the reference and insert a reference to V2.8 of glade-sharp (which does exist). Close the reference dialog and recompile. And bang, same warning and the reference has been changed back to V2.10.
Anybody have any ideas how to fix this? Or is this a known bug in that version of MonoDevelop?
If you're using the GTK version support, all the GTK-related assemblies should have the same version. I suspect that if gtk-sharp.dll is 2.10, then MD will "fix" glade-sharp to 2.10 too. In project options is a dropdown for picking the GTK version; using this will update all GTK assemblies to a specific version.
Note also that you can use the project pad to set a reference to not require a specific version.
I suggest trying MD 2.4, and if it's still an issue, please file a bug report.
Im using a market data source implementation that contains .so.0 files. However these are 'soft links' to actual .so.0.0.0 files. Why is this done?
When I try to copy these .so.0 links, it ends up copying an exact replica of the .so.0.0.0 file but with a .so.0 prefix.
Added comment:
so I have a libfoo.so file, and it is being accessed by java through jni. This libfoo.so file is actually a soft link that points to libfoo.so.0.0.0 What happens if I don't have libfoo.so. How does java/or any other compiled code, figure out that libfoo.so.0.0.0 if the shared object to use?
This is so programs can bind to either any version of libfoo that has the same interface (I want the latest updates to libfoo), or bind to a specific version (I want stability and only the exact version I tested against).
The .0 and .0.0.0 files exist so that versioning can happen:
foo.0 represents the .0 version of a library. All .0 versions of the library will use the same interface, but there may be different implementations. (Hopefully, the later implementations will have fewer bugs than the earlier ones.)
foo.0.0.0 represents a specific implementation of the .0 version.
It's not useful, now, to have the soft-link. But here's what could happen:
The programmer of foo finds a bug in his library. He releases foo.0.0.1. And foo.0 now links to foo.0.0.1. Then two things happen:
All files that link to foo.0 will automatically update to foo.0.0.1.
All files that link to foo.0.0.0 will continue to use the old foo.0.0.0