I have an application with a plug-in architecture that is using Boost.Threads as a DLL (specifically, a Mac OS X framework). I am trying to write a plug-in that uses Boost.Threads as well, and would like to link in the library statically. Everything builds fine but the application quickly crashes in my plug-in, deep within the Boost.Threads code. Linking to the DLL version of Boost.Threads seems to resolve the problem, but I'd like my plug-in to be self-contained.
Is it possible to have two instances of Boost.Threads with such a setup (one as a DLL, one statically linked in another DLL)? If so, what might I be missing to make the two instances get along?
Once my team faced a similar problem. For reasons I will not mention at this time, we had to develop a system that used 2 different versions of Boost (threads, system, filesystem).
The idea we came up with and executed was to grab the source code of both versions of Boost we needed, and then tweak one of them to change the symbols and function names to avoid name clashing.
In other words, we replaced all references to the name boost for bubbles inside the sources (or some other name) and also made changes to the compilation so it would build libbubbles instead of libboost.
This procedure gave us 2 sets of libraries, each with having their own binaries and header files.
If you looked at the source code of our application you would see something like:
#include <bubbles/thread.hpp>
#include <boost/thread.hpp>
bubbles::thread* thread_1;
boost::thread* thread_2;
I imagine some of the guys here already faced a similar situation. There are probably better alternatives to the one I suggested above.
Related
I've been writing a Python extension use the Python/C API to read data out of a .ROOT file and store it in a list of custom objects. The extension itself works just fine, however when I tried to use it on a different machine I ran into some problems.
The code depends upon several libraries written for the ROOT data manipulation program. The compiler is linking these libraries dynamically, which means I cannot use my extension on a machine that does not have ROOT installed.
Is there a set of flags that I can add to my compilation commands to make these libraries statically linked? Obviously this would make the file size much larger but that isn't much of an issue providing that the code runs at the same speed.
I did think about collating all of the ROOT libraries that I need into an 'archive' file. I'm not too familiar with this so I don't know if that's a good idea or not.
Any advice would be great, I've never really dealt with the static/dynamic library issue before.
Thanks, Sean.
newbie here.
Want to ask for any advice on how to Publish/Export, CodeBlocks Application made by using wxWidgets. After some research, i discovered that i should use DLL, or something like that, but since I am really new into it, I am missing the logic on how I should actually implement that. Since CodeBlocks offers wxWidgets and DLL as separate projects. So I am not really sure how to properly combine. Thanks in advance.
If you used wxWidgets as .dll, to get a self-standing package you have to distribute all the requested libraries. The simplest way is just to copy them from their source folder (in your case [wxWidgets root]\lib\gcc_dll) in the same folder as your executable. There could be many of them, but usually only two or three are needed. For simplicity you can copy them all, or you can try repeatedly to start the program, and add each time the library indicated in the error message.
Please note that to distribute your application you will probably want to compile it in Release mode, and consequently you should ship the Release .dlls (i.e. beginning with wx...28_ instead of wx...28d_).
I'm fairly new to OpenCV and Visual Studio as well. My question is not so much technical but theoretically anyways:
I'm working on a bigger project but do not have access to all its subcomponents etc. I wrote a few classes and functions that other members want to use. However, I'm using some OpenCV specific things (because I'm lazy and dont want to implement everything all by myself) but the other members dont use it and they want to keep the project size relatively small.
My question is: How can I provide my code as a library or something similar that includes all my opencv dependencies? Can I create a dll of my code and just ship the opencv dlls with it? Is there a way to bundle everything into one file with only one header?
How would you solve this problem?
Summarizing: I want my functions in a library and shipped as small as possible (with opencv dependencies)
KR
Put all your code in a DLL, and then ship OpenCV DLLs along with yours.
Or: put all your code in a DLL, and perform static linking with OpenCV.
I'm still not 100% sure with the framework linking process, but from what I've seen here before nobody has asked a similar question, perhaps because this could be a silly question, but I'll give it a go anyway.
In my current X-Code project, I'm using a custom framework, say example.framework. At the moment, as far as I'm aware of, in order for the program to function with the framework, I need to have it either in /Library/Frameworks, or I need to have it copied into the bundle resources in the build phase.
Would anybody know about adding a framework to a project in a way that it gets compiled into the executable, so I don't have to include the raw framework with the app? I'd rather not share the whole framework...
Thank you in advance! Any suggestions are also welcome!
A Mac OS X framework is basically a shared library, meaning it's a separate binary.
Basically, when your main executable is launched, the OS will load the framework/dylib into memory, and map the symbols, so your main executable can access them.
Note that a framework/dylib (bundled into the application or not), does not need to contain the header files, as those are only needed at compilation time.
With Xcode, you can actually decide whether or not to include the header files, when you are copying the framework to its installation directory (see your build phases).
If you don't copy header files, people won't be able to use your framework/dylib (unless they reverse-engineer it, of course).
If you still think a framework is not suitable for your needs, you may want to create a static library instead.
A static library is a separate object file (usually .a) that is «included» with your final binary, at link time.
This way, you only have a single binary file, containing the code from the library and from your project.
This I think is related to my use of the nlog C++ API (and my question on the nlog forum is here); the purpose of my asking this question here is to get a wider audience to my problem and perhaps to also get some more general ideas behind the VB6 IDE's failure to build in my particular scenario.
Briefly, the problem that I am having is that I am having trouble building VB6 components which reference unmanaged C++ components which have calls to nlog's C\C++ API (which is defined in NLogC.DLL). The build problems are not occurring during compile time, they are occurring when the binary is being built which suggests to me that it's some kind of linker type problem? Don't know enough about how VB6 binaries are produced to tell. The VB6 binary is produced, but it is corrupted and crashes shortly after it is invoked.
Has anyone had any similar experiences with VB6 (doesn't have to be related to nlog or C++)?
edit: Thanks for all the responses to this rather obscure problem. Still no headway unfortunately; my findings since I posted this:
'Tweaking' the compile options doesn't appear to help in this problem.
Adding a reference to the nlog-enabled C++ component from a 'blank' VB6 project doesn't crash it or cause weird build problems. So it isn't a 'native' VB6 issue, possibly an issue with the interaction between nlog and the various components and 3rd party libraries used by other referenced components?
As for C++ calling conventions: the nlog-enabled C++ component is - as far as I can see - compliant to these conventions and indeed works fine when referenced by VB6 as long as it is not making any nlog API calls. Not sure if the nlogc.DLL itself is VB6 compliant but I would have thought that that is immaterial since the API calls are being made from the C++ component; VB6 shouldn't know or care about what the C++ component is referencing (that's as far as my understanding on this goes...)
edit2: I should also note that the error message obtained during build is: "Errors during load. Please refer to "xxx" for details". When I bring up the log file, all that there is in there is: "Cannot load control xxx". Interestingly, all references to that particular control disappears from that particular project resulting in compile errors if I were to try to build again.
Got around the problem by using NLog's COM interface (NLog.ComInterop.DLL) from my unmanaged C++ code. Not as easy to do as the C\C++ API but at least it doesn't crash my VB6 components.
I would try tweaking some of the Compile options found in the Project, Properties menu, Compile panel to see if they yield any additional hints as to what is going wrong.
For example if you compile the executable to p-code rather than native code does it still crash on startup.
What error message do you get when you run your compiled binary?
I doubt the compiler/linker is the problem: project references in a VB6 project are not linked into the final executable. A project reference in VB6 is actually a reference to a COM type library (which may or may not be embedded in a .dll or other binary file type). Project references primarily serve two purposes:
The IDE extracts type information from the referenced type libraries which it then displays in the Object Browser (and in the Intellisense drop-down)
At compile-time, the compiler extracts the type information stored in the referenced libraries, including the CLSID of each class that you instantiate, and embeds this data into the executable. This allows your executable to create instances of classes contained in the libraries that you referenced.
Note that the compiled binary doesn't link to any code in the referenced libraries, and it doesn't even contain the filenames of the referenced libraries. The final executable only contains the CLSID's and other type information that it needs to instantiate COM objects at run-time.
It is much more likely that the issue is with NLog, or with how you are calling it from your code, rather than something gone awry in the VB6 compile process.
If you think it might be a linker problem, this should crash it the same way:
create a new standard project (of any kind)
add a new module and copy the "declare"-statements into it
compile
If it doesn't crash it is something else.
It would help an exact description of the error or a screenshot of what going on.
One thing to check is wherever NLogC.DLL or the C++ DLL you built have the correct calling convention defined. Basically you can't have the DLL function names mangled or use anything but the STDCALL calling convention. If the C++ DLL has not been created with those two things in mind then it will fail to work with VB6.
MSDN Article on Calling convention.
"Cannot load control xxx" errors can be caused by .oca files which were created from a different version of an .ocx than currently used. If that is the case, deleting the .oca files helps.