after searching a lot, i am still unable to find one thing that whether can i use a lib***.a in my .java file or not.
i.e:
static {
// Library
System.loadLibrary("***");
}
i got this doubt when i read the line You must provide a native shared library that contains the implementation of these methods in the overview.html.
so can any one tell me whether can i use lib***.a in .java file or not.
If yes then how?
since you should not use the 'lib' prefix and '.so' suffix here. is written in the overview.html.
It seems that you can't. As far as I know, the Java native interface uses dynamic libraries to load code runtime; I'm sure that cannot be done with archive libraries (.a).
Related
Say I have a binary server, and when it's compiled, it's linked from server.c, static_lib.a, and dynamically with dynamic_lib.so.
When server is executed and it loads dynamic_lib.so dynamically, but on the code path, dynamic_lib.so actually expects some symbols from static_lib.a. What I'm seeing is that, dynamic_lib.so pulls in static_lib.so so essentially I have two static_lib in memory.
Let's assume there's no way we can change dynamic_lib.so, because it's a 3rd-party library.
My question is, is it possible to make dynamic_lib.so or ld itself search the current binary first, or even not search for it in ld's path, just use the binary's symbol, or abort.
I tried to find some related docs about it, but it's not easy for noobs about linkers like me :-)
You can not change library to not load static_lib.so but you can trick it to use static_lib.a instead.
By default ld does not export any symbols from executables but you can change this via -rdynamic. This option is quite crude as it exports all static symbols so for finer-grained control you can use -Wl,--dynamic-list (see example use in Clang sources).
I am trying to write source code in one language and have it converted to both native c++ and JS source. Ideally the converted source should be human readable and resemble the original source as best it can. I was hoping haxe could solve this problem for me. So I code in haxescript and have it convert it to its corresponding C++ and JS source. However the examples I'm finding of haxe seems to create the final application for you. So with C++ it will use msbuild (or whatever compiler it finds) and creates the final exe for you from generated C++ code. Does haxe also create the c++ and JS source code for you to view or is it all done internally to haxe and not accessible? If it is accessible then is it possible to remove the building side of haxe so it simply creates the source code and stops?
Thanks
When you generate CPP all the intermediate files are generated and kept wherever you decide to generate your output (the path given using -cpp pathToOutput). The fact that you get an executable is probably because you are using the -main switch. That implies an entry point to your application but that is not really required and you can just pass to the command line a bunch of types that you want to have built in your output.
For JS it is very similar, a single JS file is generated and it only has an entry point if you used -main.
Regarding the other topic, does your Haxe code resembles the generated code the answer is yes, but ... some of the types (like Enum and Abstract) only exist in Haxe so they will generate code that functionally works but it might look quite different. Also Haxe has an always-on optimizer/analyzer that might mungle your code in unexpected ways (the analyzer can be disabled). I still find that it is not that difficult to figure out the Haxe source from the generated code. JS has support for source mapping which is really useful for debugging. So in the end, Haxe doesn't do anything to obfuscate your generated code but also doesn't do much to try to preserve it too strictly.
I've looked around (including StackOverflow), but the only question close to mine, as far as I can tell, is specific to Windows distributables, which doesn't apply to me.
I want to release a library: MyLibrary.lib
It uses some third-party libraries, for instance, ZMQ
I've included the third-party library into MyLibrary both with either #pragma or actually adding it to the project.
Either way, MyLibrary.lib compiles fine and creates a .lib file
HOWEVER.
An executable that is linked to MyLibrary complains at link time that it can't find the referenced ZMQ functions, as if ZMQ is not incorporated into MyLibrary.
Looking at MyLibrary with a hex editor it doesn't seem like ZMQ.LIB was incorporated. There are references to it but it seems "weak linked". I don't see the ZMQ code in there.
Alternatively, if I can get the application/executable to build and run it, it'll complain at runtime that it can't find zmq.dll.
Either way, it's obviously not in "MyLibrary".
How can I get a library to include other third-party libraries, so I don't have to distribute a bunch individually? What step am I missing?
Using MSVC2013
Thanks
Although I had the .lib I needed, it turns out it was an import lib, and the .dll was distributed elsewhere. I found the .dll and now it works. Thanks to all who responded.
What about the flags described in this article:
https://msdn.microsoft.com/en-US/library/2kzt1wy3%28v=vs.120%29.aspx
Can they help you?
Can anyone explain to me how to use ReaderWriterOBJ in OpenSceneGraph? I want to load an obj file along with the mtl file. I have already built the solution for readerWriterObj code and created a dll file.
The ReaderWriter's are just file loaders. You have to use them in context of an application, like osgviewer, one of the examples included in OSG. If you've gone through the process of building OSG, you might have already built osgviewer, which will use the appropriate DLL's to load files.
eg
osgviewer FILE.obj
will open FILE.obj, with its associated material file[s].
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.