Libraries like curl require you to have .dll files when running .exe
In theory you should be able to link those .dll statically to the .exe
But I can't find a way to do that without errors and crashes.
But are there libraries which don't require external .dll files at runtime?
That allow me to do a HTTP request?
Libraries like curl require you to have .dll files when running .exe
In theory you should be able to link those .dll statically to the .exe
No you can't. They are dynamic link libraries. DLLs can't be linked statically. If the supplier also supplies a static .lib file, you can link that instead of the DLL. It isn't the same thing.
But I can't find a way to do that without errors and crashes.
Unsuprising, as there isn't one.
But are there libraries which don't require external .dll files at runtime? That allow me to do a HTTP request?
Very likely, but why? What's your objection to DLLs?
From my experience, the .lib you are linking is not the dll's implementation, it just contains some metainfo on the dll.
If you are trying to convert a .dll to a .lib, this may help (but it is daunting):
http://adrianhenke.wordpress.com/2008/12/05/create-lib-file-from-dll/
If everything fails, you should consider compiling static version of libcurl on you own
http://fluxxu.com/2010/12/08/building-static-libcurl-with-ssl-support-on-windows/ (note: export CURL_STATICLIB in your app)
Building libcurl with SSL support on Windows
Related
I'm fairly new to C++ and I know how to link external libraries in Visual Studio, but I'm not sure how to include them with the .exe file that is made when you build. How do I include a library with that so the other PC doesn't have to have the libraries installed in the same exact location on the disk that I do (or in other words just with the application)? I tried putting the .dll files directly with the .exe but it says it can't locate them.
This depends on the type of linkage that you use for the library. You basicaly have 2 options:
static linking
dynamic linking
When you statically link your program with a library, that library is embedded into the resulting application (exe). So you need to distribute only that resulting application.
Or the library can be linked dynamically. This means that the actual library code will be looked up at runtime (by OS) from dll file (on Windows). In this case you must be sure, that user will have dlls you need on their computer. To see where Windows searches for dlls see this msdn page. Basically you want your dlls to reside in the folder, where your program is, so Widnows can find it. Or if you are using some system libraries (e.g. Direct3D) your user will probably have those dlls already installed.
I have some confusion about static and dynamic linked libraries and .lib and .dll files.
I have a project with two libraries, one I built myself and one is from an open source library.
The one I built myself is a separate project in the same solution (Visual Studio 2015, C++), and I don't need to copy over the .lib files or create a DLL for the executable to build and run
For the other open source library, I do need to copy over the .lib file and the DLL into the executable folder. However, I thought it would be possible to statically link a .lib file and not have to copy over the DLL.
Does this mean I need to compile the Open Source library differently? Like change the define __declspec(dllexport) to __declspec(dllimport) ? Or change /mD to /mT in compiler options?
I tried both of these, but it's still saying that it can't start without the .dll
Or can I get away with changing a setting in the executable project to link this library statically? If so, what are these settings?
EDIT: I know this is a standard question that can be looked up on google, but I haven't been able to find an exact answer for a while. Mainly, I'm confused about what settings need to be changed, and which project they need to be changed in. (The library or the executable).
I'm under assumption that static linking means the library is built into the executable, and dynamic linking means the library needs to be in a separate file, if this is incorrect, please let me know. Otherwise, I need to know how to build the library into the executable file.
And I can go ahead and change the build options in the open source library, and I tried this already.
Thanks,
-D
In Windows, dll files (dynamically linked libraries) need to be in the same directory as the application or on the search path. lib files (static libraries) need to be statically linked during linking (the last step of building the application). It's common in Windows so have a library come with both a dll and lib file. In this case, the lib file is an import library containing the information needed to easily link to the dll.
Place the dll file where your application will be built and statically link with the lib file. Go to 'Project->Properties->Link->Input->Additional Dependencies' and 'Project->Properties->Link->General->Additional Library Directories' to specify the static libraries you want to link.
Edit: It seems I misunderstood the question. The question is how to recompile a dynamic library as a static library. You need the source code of the library you are using along with it's Visual Studio Project file. Open the library and in `Project->Properties->General->Configuration Type' change it from Dynamic Library to Static Library.
Beware that Dynamic Library uses the Linker group of properties while the Static Library uses the Librarian group of properties. Changing between these types may cause the project to drop essential linker flags options. Since every library is different, I can't predict what you will have to do work around this. Make sure to backup the project file so you can see the original options and flags.
I had to change the setting for "Static Library" for All Configurations, not just Debug, although it was building in Debug. Not sure what may have caused this. Possibly because the debug and release builds for the library were set to the same folder, it may have been overwriting the debug builds with release builds when building
I want to use the functionality of a 3rd party dll into a lib I create.
Something like this:
m_hLib = LoadLibrary(L"Bla.dll");
and the using this with:
void* fnBla = ::GetProcAddress(m_hLib , "MethodFromBla");
to use some stuff from the respective method.
Now my question would be: could I build the lib like this and then use its functions from an exe?
No Problems at all . exe gets statically linked to the lib file . That means lib code becomes part of exe code . Now the exe code is loading the dll dynamically :)
What you're doing is dynamic (or runtime) linking, ie you explicitly load the .dll and resolve the functions via GetProcAddress. If you're doing this then you don't need a .lib file.
A .lib file is only necessary if you want to statically link against the .dll at compile time. The linker takes the .lib file and resolves the references in your program against the functions information in the .lib. Therefore, if you don't plan to link to the .dll at compile time you won't need a .lib. You just need to make sure that the .dll (Bla.dll in your case) it released alongside your application.
I'm trying to use libcurl library in my application.
when i start my application, it asks for libcurl.dll and zlib1.dll
to exist in the same folder. when i add them everything works fine but i want to include
them to the executable.
how can i statically add both dll's to the application?
You cannot statically link dlls into an executable. The purpose of dynamic libraries is to be loaded dynamically during runtime from an external image (dll file). You should check whether curl and zlib provide proper static libraries and link against them instead of lib stubs for the dlls.
Consider that linking against static external libraries makes your binary potentially vulnerable against any security issues in statically linked blobs. That means that you will have to update any binary you statically linked against those libraries instead of simply updating the libraries themselves.
I'm trying to add PNG support to my application and thus I want to include libpng. I know it needs zlib and thus I downloaded that as well. I went into the png folder/projects/vstudio and I opened the solution. I compiled it and it went just fine. I added some headers from it into my application and I copied the lib files. My program is a dll written in c++ which is later used from C#. When I run it in C# it complains about not finding my dll (tough if I remove the png part it works fine). I've had this problem before and it usually means a dll dependency is wrong.
Now... libpng compiled both some .lib files and some .dll files. The dll files are bigger. My only guess is that it needs the dll files as well but I've seen that people can link to libpng without a dll.
So my questions is: How can I compile libpng(and zlib for that instance) into just static libraries and how can I include those in my projects? I've searched around the internet and I couldn't find anything useful.
To make all your libraries static, you would have to recompile everything "from scratch" as static libraries.
This simply means you should create a set of projects for each library you have in your sequence and set the output type to static library.
After that you should eliminate library dependencies between the libraries themselves (this means you should link the output of some projects to another projects, e.g. if your "libpng" library uses "libzip", it means you should first compile the "libzip" and link that output (static library) to your "libpng" project.
In the very end you would have a big set of static libraries compiled for your platform, which you can use in your projects.
Also to mention, try googling more carefully. I'm sure someone has this done and you would probably need to download a package of .lib files for your platform (I know that very often the "dev" bundle of libraries only includes an import library paired with appropriate .dll file, but there are a lot of enthusiasts like you :)