How to sqlite3 dll without use? I'm imported sqlite3.h and sqlite3.lib, and error sqlite3.dll not found. Need run without sqlite3.dll.
This is not how it works. If the .lib is compiled to be dynamically linked then it just exports the list of symbols available inside the dll but the code still resides inside the dll.
If you want to avoid using dll, you need a static version of the library, I don't know if it's already provided by sqlite, otherwise you need to compile it yourself, this could help you.
As far as I know sqlite3 is a single source file. Just add it to your build and you should be golden.
Related
I am making a win32 console app using msvc++ that is going to use a really simple dll. I put my .lib and header for my dll (my dll only has one header) into my console applications folder.
When I run it, I don't get any compile or linking errors, but when the app is actually open, it says it cant find the dll. When I put the .dll file into the console app's folder and run, it actually works. I would like to know why this happens??????
Look at this link:
Dynamic-Link Library Search Order
Windows has a DLL search order. You can change it by functions specified in the above link.
Your import library is used to define information about functions in your DLL and so. You can use LoadLibrary("myDLL.dll") function to load DLL without header.
In this case you must use GetProcAddress(module, "function_name") function to get function adresses in your DLL.
GetProcAddress function
and here is the link where is some solution for GetProcAddress():
Calling functions in a DLL from C++
I've knowledge of C++ and compiling small plug-ins (always based on a similar and laid out workflow). Though currently I need to compile the latest version of FFTW into a static library (or get it from the compiled version which should supposedly be a lot easier) and it's giving me an insanely hard time. Probably because I don't know the ins and outs of compiling. As a note I'm working on Windows with Visual Studio.
Since I really want to know how this should work I'm asking the question here.
Basically I need a static .lib of fftw3f library on Windows that I can include in another Visual Studio project.
The first I did was download the 64 bit dll's of FFTW from the website (hoping I could use this).
http://www.fftw.org/install/windows.html
Then I've done the accompanying step they stated, that is:
Run the following in lib.exe.
lib /def:libfftw3-3.def
lib /def:libfftw3f-3.def
lib /def:libfftw3l-3.def
I've done this as well and got a .lib file that I could use in my project correctly. I've been able to compile my project, yet the output build apparently dynamically linked to the library instead of including it as a static library.
I'm compiling my project to .dll but require the fftw3f library to be statically included in my output.
Using lib.exe /list libfftw3f-3.lib I was able to find out that the lib file was referencing the libfftw3f-3.dll.
According to my google results this would mean the .lib file that I created is a DLL import library instead of static library.
It's hard to figure out how to phrase my question because I'm not sure what the terminology is and what's going on behind the scenes. I guess:
How can I use the libfftw3f-3.lib file created from lib.exe as a static library in my own project. So that it is included in my output .dll instead of dynamically linked?
Based on what I learn from comments/answers I'll be happy to update/edit/rephrase my question to make more sense for most other users as I'm likely way of with the terminology
You cannot expect to convert a DLL into a static library.
In order to create a static library you need to re-compile the library from its source code, with an output target that is a static library. If you cannot obtain the source code, then your goal cannot be achieved.
I'm working on a library project which is pretty much finished. So I'm giving it a test run now. I have no problem running my test project. However I'm not entirely sure if I'm doing it right. Mainly because I don't really understand what is happening exactly( at least im not entirely sure).
I've compiled both the DLL and Static library(.a). For my test project i'm using the Headers from my library and linking against the static library. I'm able to compile. But then It seems that I also need the DLL where the executable resides in order for it to run.
So to my understanding, I compile using the static library but I don't exactly embed it into my executable, therefor at runtime it's looking for the DLL?
My confusion comes from the fact that I read that static libraries are usually embedded into the executable. But doesn't that only happen if you specify that in the compiler options?
I'm rather confused about the relationship in my sittuation. Can someone clarify this?
Edit:
I'm using GCC.
Codelite as my IDE.
lib is static (cannot be dynamically linked at run time) at compile time. So you are correct that the lib is "embedded" in the executable. More precisely, the lib is linked to other object files that the compiler has produced to build the exe file. A lib cannot link to another lib, only an exe or a dll can link to a lib.
dll is dynamically linked by the exe while the exe is run. dll is like another exe, but its entry function is "dllmain" instead of "main". dll can be built with lib's just like exe. dll can also link to other dll's at runtime to interface with these dlls' functionalities. The interface to dll is defined by a def file.
As to why your project would need the dll, you might want to check the calls of LoadLibrary in your project.
I'm developing an application at work using C++, Qt, Mingw32 and Netbeans. I need to use an in house API that has been developed by the software group in the company.
I have the symbol libraries .lib files for the DLLs i need to link against, but i cannot use these libs with Mingw32, it works fine with Microsoft Visual Studio.
Does anyone know if there is a way to export the symbols and create a .a symbol library that works with Mingw32 ? If not i'll have to go over to Visual Studio i guess.
I have tried using the program "pexports" to create a .def file and dlltool, but that didn't work. Still got unreferenced symbol errors, then i added the symbols it complained about to the .def, because they weren't there and it stopped complaining and compiled. But the program crashes. I tried the same code in Visual Studio and it compiles and runs fine.
Have you considered dynamically loading the DLL? LoadLibrary, GetProcAddress, etc. You can probably easily write a class that encapsulates all the DLL's entry points, loading and unloading the library, and does all the #typedefs, etc. It's grunt work but if it's an in-house library there probably aren't too many entry points?
Import libs are overrated. :p
Not sure if it helps, but you may wish to check this guide.
Here's how I did that for the mysql library.
Create a list of exports using dllwrap:
dllwrap --export-all-symbols --output-def libmysql.def libmysql.dll --implib liblibmysql.a
This creates a list of exports in the .def file but the name mangling is incorrect.
Edit the .def file in a text editor and remove the '#' symbols.
The symbol names typically also have a number appended to them as well.
I don't know how to determine the correct name except by experimentation:
Run the following to create a netbeans compatible library:
dlltool --input-def libmySQL.def --dllname libmySQL.dll --output-lib libMySQLclient.a -k
Compile with it and you'll get undefined symbols. The undefined symbols will have the correct decorations.
Edit the .def file again and correct the symbol names. Re-run dlltool to get the correct .a library file.
Have you tried linking the DLL directly, rather than a .a/.lib? MinGW is usually happy to do that for you.
I give up, some people say it is not possible with a dll compiled on microsofts compiler with c++ exports, because of the name mangling
It's pointed out by this answer:
Failed to link mysql5.1.39\bin\libmySQL.dll
But I don't understand why,.dll is essentially the same as .lib except for there is only one copy of it used by different processes.
Does it have anything to do with the IDE?I'm using visual c++ 2008 express
UPDATE
Anyone know a free tool to convert .dll into .lib in windows?
You are wrong on two counts. Firstly, DLLs and LIBs (static libraries) are very different beasts. The LIB you are talking about (I think) is the export library, which is simply a list of names in the DLL. This library is typically produced when the DLL is compiled and is shipped with the DLL if the DLL is intended to be linked to by other developers.
To use a DLL with a modern IDE (I don't use VS) you typically include the matching .LIB (export library) in the project. At run-time you must make sure the DLL is available to your program - the simplest way to do this is to put the DLL in the same directory as the executable.
And secondly, DLLs can be used with C++.
DLL are specific windows executables which load on runtime. Their equivalent in Linux is the *.so .
If you want to understand what's the difference between a DLL and a static lib see here.
Main reason has probably something to do with dll-file being an output of the linker (link.exe). This command line utility doesnt know how to read dlls, only how to write them.
Actually sometimes .lib-files contain more than a list of functions. For example libpng.lib works as a standalone file, without any dll file.
In order to use a DLL in C/C++ you need to link with what is called an import lib. This is a small .lib that contains the names/ordinals the DLL exports in a format that the linker understands. Once this has been linked in, the resulting binary will be able to use the DLL. If you do not have the appropriate import lib, your C/C++ compiler should come with a tool to generate one from the DLL.
You can use the following analogy to understand the difference between a dll and a lib file.
the dll is like the source .cpp file while the lib is the header .h file.
While this is not exactly true, the DLL holds the executable code while the LIB file tells the linker how to glue the code together.
It is also possible (in some cases) to generate the lib from the dll. Basically, all you need to know to call a function is the function entry point in the dll, the number of parameters and the size of each parameters. Sending relevant information is then your own problem.