I am creating a project using mingw under windows. When run on another PC (without wingw in PATH, respectively), get errors, missing: libwinpthread-1.dll, libgcc_s_seh-1.dll, libstdc++-6.dll. How can I build the project so that everything starts up normally?
A C++ program needs runtime libraries to run. They're usually not part of the program itself! So you'd need to ship these libraries alongside with your program (which is what most software does).
You can, for many things, however, also use "static linking", which means that the parts of the libraries used by your program are included in your program itself! The -static flag supplied to executable-generating step in your project will do that. If your program consists of but a single file, that would be g++ -o test -static test.c (your g++ might be called x86_64-w64-mingw32-g++ or so).
If your distributed .exe file won't run because of missing .dll files that's because it is linked against those files and you need to distribute these files with your .exe file.
But actually there are 2 solutions to this problem:
Shared build (= using .dll files): distribute the .dll files with your application. The best place to put the .dll files is in the same folder as the .exe file(s). You can use Dependency Walker to figure out which .dll files your .exe file needs (and which .dll files those .dll files need etc.) or you can use the command line tool copypedeps -r from the pedeps project to copy your .exe file(s) along with any .dll files required.
Static build (= everything rolled into the .exe file(s)): when building your .exe file(s) use the --static linker flag (and if needed also -static-libgcc and/or -static-libstdc++). This create a static .exe file, which means all the static libraries are rolled into the .exe file. This may make your .exe quite large (though you can try reducing its size with the strip command or the -s linker flag) and doesn't have the advantage of .dll files where common code is only distributed once. It may also cause longer loading times for your application, since everything is loaded at once.
Related
I want to package my executable file and other needed files into an install file (using NSIS) so that other people can install and use. There are a few file types I am uncertain of whether they are needed for installation or if it is safe to delete them.
Here is a random example of the files in the project folder as well as the Debug file automatically generated by VS:
I have already deleted the .user file as I know that is not needed, but not sure when it comes to .vcxproj, .tlog, .build.cppclean, .idp, and .pdb files. Also, do I need to keep the .obj files as well as the .cpp files?
This is my first time trying to do this, I am just messing around to seeing how it all works so thanks in advance.
You generally only need the .exe. Your app might depend on custom .dlls or the C++ run-time library in which case you would bundle the custom .dlls and/or the C++ redistributable.
Your screen shots are of a debug build and you normally want to distribute a release build instead because it is often smaller and contains more optimized code.
.obj files contain the machine code for each source file and is used by the linker when it merges all the required code into your .exe.
.pdb files contain debugging information. You should not distribute them but it is helpful to store them for yourself in case you need to debug a released version of your application.
The rest of the files in Debug and Release can also be ignored.
If your project is open source then you could include the c/c++ files and the Visual Studio project files. Or you could just upload them to Github.
In NSIS you could do something like this
InstallDir $ProgramFiles\MyApp
Page Directory
Page InstFiles
Section
SetOutPath $InstDir
File myproject\Release\MyApp.exe
File mylibrary\Release\*.dll
SectionEnd
It is a good idea to test your installer on a freshly installed Windows instance. Ideally the minimal version you require, Windows 7 etc. This should allow you to verify that you have included all the files required by your application.
According to this question,
Dynamic linking is done at run time, by the operating system.
Until now, using g++ with eclipse CDT, I statically linked odbc32.lib I got from windows SDK to get some ODBC functions to my program. But I deleted the file by accident and was surprised to find my program still running and connecting to the database. Since the file no longer existed the the path I specified to the -L option, I thought it must still exist somewhere in one of the subfolders of the path. But then I deleted the library path to see what happens but my program still works! I began searching for odbc32.lib and I really can't find it. However, I do found a odbc32.dll file located in C:\Windows\System32 and I thought it might be dynamically linked to my program.
If I'm right, How does the compiler find odbc32.dll when I never specified C:\Windows\System32 as my library path?
To test my theory, I began grabbing many .dll files in the system32 folder and linked them using -llibrary. I've managed to link some of the files I got because my program run successfully, but some files can't be found by the linker, why is that?
Am I right? Is this an example of dynamic linking?
Note: I also removed C:\Windows\System32 from my path but it's still, for some reason, working.
From your comments, you stated you are using g++ with cygwin. Basically this means that linking is now done as it is on linux (or unix or whatever) and one library is needed. In your case this is static library so it links upon compilation and doesn't need it again.
I implemented the SFML library nightly build to my Visual Studio 2013, because the original one is not compatibile with this VS version. I done everything what is needed (added directory to include folder in both Debug and Release, added directory to .dll files), but it can't find the files in program. What else should be done to make this library work? Or should i consider changing Visual Studio to 2010?
You haven't given really to much information so I am just really guessing as to what the problem is.
added directory to .dll files
But that sounds like your problem right there. You don't add the directory that the .dll files are in to your project. The only directories you need to add to the project are the include directory and the library directory.
But anyways I am assuming you are using dynamic linking since otherwise you wouldn't be dealing with .dlls. Now different IDE's require that you place the .dlls in different spots but since you are dealing with VS2013 you need to copy whatever .dlls that you are using into the same folder where your program's compiled executable is (The .exe file).
Another option is to link statically instead of dynamically which I generally prefer to do on small projects but it is really up to the developer which he prefers.
When you link statically you don't need to include any .dlls. What you will need to do is recompile SFML's sources and make sure to build the library so it produces the static library files (They should be named something like sfml-graphics-s-d.lib for debug and sfml-graphics-s-d.lib for release).
Add that library directory which contains the static library files to your project and then link to them .lib files in VS's input window (Remember that -d is for the debug build).
Next you will need to add SFML_STATIC to your preprocessor options on both the release and debug build.
After that you are good to go and don't need to include the .dll files with your project. And again whether you choose to link dynamically or statically is really up to you and the project you are working on but for small projects I would suggest linking statically.
I'm trying to understand what exactly all of these are and how they relate to each other (and most importantly, how to install them).
From what I've read, LIBs are libraries linked during the compilation of my project and DLLs are libraries linked during the runtime of my project.
So for me to use a LIB, I have to have the actual .LIB file somewhere in my computer, go to Project -> Properties -> VC++ Directories and add the path to the file in the Library Directories, and after this I have to go to Linker -> Input -> Additional Dependencies add the .lib name in there, and finally I need to type #include in my code, right?
So, some questions:
When I finish and build the release of my program, will the .exe only run if the target platform has the .lib installed in their PC as well? If yes, what steps do I need to do to make sure the .lib goes with the .exe?
When I get the source of a open source project, if I add them (using Add Existing Item...) to my project, can I use them just by using #include as if the files were mine and it would be the same as having the .lib installed? Or do I need to install the .lib file and still use these source files?
I have a project using OpenGL and I linked to glew32.lib, but I don't have the lib or any new directory added in the VC++ Directories, so I think this means I must've installed the .lib in the system folder or somewhere where the Visual Studio won't ask for another directory, should I worry about this when releasing a project?
How the above questions relate to DLLs and is there any reason why should I use DLLs over LIBs or the other way around?
I'm starting to use more and more libraries and I noticed I just dragged, copied and included it everywhere so I could use them but never really understood how they "fit" in the project. Especially those open source libraries where they provide so many files and I don't really know what to do with them...
You don't need to have LIB files along with your EXE file for running in another computer, LIB files are static files and DLL files are dynamic. So when you compile all static codes will be included in your EXE file, but DLL files will be loaded and used dynamically in runtime, so you just need to have your DLL files with your EXE file. This way, your code will work and run properly in other computers.
Just adding another project is not enough, you need to compile them and generate LIB files out of them. Then you add the generated LIB file to your final project and include external projects in your final binary. If you are compiling multiple projects together in a solution, you'll need to set project build order in solution properties in VS.
No, that's OK. It seems you've put LIB files in right folder and you don't need to have LIB file with your EXE file to run it in other computers.
DLLs are dynamic libraries, so you need to have them with your application. Installers usually install EXE files with DLL files in the same folder, so your app will run properly, but no need to include LIB files at all.
Also you can include LIB files like this:
#pragma comment(lib, "glew32.lib")
So you don't need to do it in project settings, but assuming you have your LIB file in "Library Directories" path.
Using DLL files can be done in two ways:
One is linking your application to DLL file and having DLL file's function entry in your EXE file's import table:
like using
#include <windows.h>
then
GetWindowsDirectory(windir, MAX_PATH);
So you'll have GetWindowsDirectory API entry in your EXE file's Import Table.
Also you can do it dynamically:
hinstDLL = LoadLibrary("kernel32.dll");
if (hinstDLL != NULL)
{
func_GetWindir = (DLLPROC) GetProcAddress(hinstDLL, "GetWindowsDirectoryA");
...
There is not much difference, only difference is:
In first method, as it's in your EXE file's Import Table, if there was no kernel32.dll or there was no GetWindowsDirectory entry in kernel32.dll, your EXE will not run at all, it will show a critical error and will not run. But in dynamic way (second way), your app will run, but as soon as your code try to use GetWindowsDirectoryA API, it will fail. You will have 0x00 in func_GetWindir. If you attempt to call it, then program will crash.
I made a program with Microsoft Visual Studio 2010. It uses additional libraries (Allegro), and it runs perfectly from MSVC, but I can't run it from it's directory. (...\"project name"\Debug\"project name".exe) It writes that it can't find some kind of .dll files.
That's not good, because I want to make it work for everyone! What to do to make it work?
I know that I have to put the necesarry .dll files, but I don't know where?
When an executable is started, Windows searches the current directory, the PATH and then some other places. The exact description can be found here
You need to make sure either the PATH includes the library you need, or place it in the same directory (or in some other automatically searced directory, but that's typically not a good solution).