I looked at many places but could not find anything telling me how to buld the lib files. I know how to link them, but openCV install folder only contains .a files. I cant find an sln file or dsp. How can I make the lib files? Right now all the samples get linker problems because the lib files dont exist.
Thanks
The Windows installer (.exe) for OpenCV 2.0 does not come with the binaries pre-built for vc++, nor does it have the .vcproj files for using vc++ to build them. You need to have cmake, which is available for free on the web. I used the GUI. Use that to build .vcproj files with which you can compile everything in VC++ 2008 or whatever. There are some gotchas. The question has been asked and answered.
.a files are libraries. On a unix platform they're typically statically linked libraries.
If you're on windows however they should be .dll files. How did you compile OpenCV and does it support compiling on windows?
In order to create the .sln files you need to run CMake on the OpenCV folder containing makefiles.
Related
I'm working with Embarcadero C++Builder 10.3.3, and would like to use OpenCV with it. However, the precompiled OpenCV pack is precompiled with Visual Studio, which uses the COFF format. However, the C++Builder 64-bit compiler uses the ELF format under Windows, per Upgrading Existing C++ Projects to 64-bit Windows:
Object and Library File Format
BCC32 and its associated tools use OMF in .obj and .lib files.
BCC64 uses ELF in .o and .a files.
Of course, I tried to compile the OpenCV source code with C++Builder, but I failed miserably. A Google search didn't find anything really helpful either, except that others also didn't succeed.
Does anyone know a CMake-compatible compiler that can generate object files (.o) and static libraries (.a) for Windows to compile OpenCV (for Windows, not for Linux, because BCC64.EXE is a Windows compiler)?
I'm also trying to use OpenCV with C++Builder (I couldn't write a comment because this is my first contribution!).
I could create the lib file with mkexp from the precompiled dll (opencv_world452.dll in \opencv\build\x64\vc15\bin) as Remy suggested.
But I have problems with the header files: How to set include path that the statement #include "opencv2/core.hpp" is accepted by the compiler? "core.hpp" also has such include statements. So, do we need to change all these #includes (\ instead of /)?
As a workaround you could try to use the Delphi-OpenCV library (https://github.com/Laex/Delphi-OpenCV) or install Python4Delphi in C++Builder and use OpenCV via Python.
I work on a project that generate several static libraries (.a) from MinGW with Scons project files.
And I need to use these libs into an other project that work on C++ Visual Studio 2013.
First I tried to just add MinGW lib to my VS project and obviously it didn't work out.
I read some things about using a ".def" file to switch from ".lib" to ".a" but found nothing about convertion from ".a" to ".lib". But I have no idea how to get this ".def" file.
Does anyone have some clue that what I am trying to realise is possible (use MinGW into VS2013) ? Or even a solution that can help me :)
Mathieu.
I am a Python developer and I have not used C++ since university. I am doing scientific programming with python, mainly. I wanted to try C++ to see if it is better performance-wise.
I am quite new in C++. I have found dlib library, which seemed a good library as it had many interesting features. But when I downloaded it, I found several folder full of .h and .cpp files.
In Python, I would have installed a wanted library using pip or something, then use it in my project using import.
Is there a similar installation for c++ libraries? Or do I have to look among all those .h and .cpp files and decide which ones I need in my project then copy them? Or how do I use the dlib library?
I have searched a lot on google but I could not find any indication on how to use a c++ library or install a new package to be used.
I use Visual Studio Community 2017 and Windows 10 if that matters.
To integrate a library, you need two kinds of things:
header files (usually *.h) with the declarations required to let the compiler know about the features in the library (a little similar to an import statement);
compiled library files (usually *.lib) containing the precompiled executable code itself, to let the linker assemble the final executable file.
In some cases (especially for templated code), a library can be made of header files only. In other cases, the package doesn't contain a ready-made library file and you have to build it yourself or manually include the source files (*.c/cpp) in your project.
Not speaking of the innumerable optional settings that you may have to adjust to comply with the specifics of the generated code, such as function calling convention, struct alignment...
Last but not least, some libraries are connected to at run-time only. They are called Dynamic Link Libraries and involve yet different procedures.
All of this is relatively complex and close to black magic for beginners. If you are very lucky, you will find some library documentation telling you which options to use for your compiler. If you can, start from an existing sample project that works!
For dlib, check http://dlib.net/compile.html.
Be ready for a cultural shock when you will compare to the ease of use of the Python modules.
It is quite a broad question, but I'll do my best.
First of all, in C++ libraries consist of header files and precompiled part (.lib,.dll on Windows, .a, .so on Linux). To use them in your project you have to inform your program (and compiler) about features that library has (by #including their header file) and linker to include that library binaries.
pip is package manager, which automatically downloads, builds and installs library that you want in your system. In C++ there is no such single tool at the moment and there steps must be done more or less manually.
For dowloading you usually end up with git or downloading the zip archive with source (do it here). Once you have sources you have to build it.
In order to achieve multiplatformity libraries usually does not get shipped with concrete build system description (Visual Studio Project on Windows or makefile on Linux etc.), but are created in more general tool CMake, which abstracts them. E.g. dlib does that. With use of CMake (For start I recommend CMake-GUI, which is installed with CMake on Windows) you can generate Visual Studio Project, which later you can open and compile to generate .lib file. How exactly to do it follow dlib compilation description.
Once you have you lib and headers files on your disk you can add headers and .lib to your Visual Project and use as any other C++ library. (Seems old, but should work)
As far as I know, there are no tools similar to pip for C++. What you have to do depends on your working environment and the respective library.
In case of dlib there are instructions on the project homepage for Visual Studio. Basically, it involves compiling the whole library alongside your own project by copying a single source file to it and setting up include pathes.
From http://dlib.net/compile.html:
Compiling on Windows Using Visual Studio 2015 or Newer
All you need to do is create an empty console project. Then add dlib/all/source.cpp to it and add the folder containing the dlib folder to the #include search path. Then you can compile any example program by adding it to your project.
Again, note that dlib will only be able to work with jpeg and png files if you link in libjpeg and libpng. In Visual Studio, the easiest way to do this is to add all the libjpeg, libpng, and zlib source files in the dlib/external folder into your project and also define the DLIB_PNG_SUPPORT and DLIB_JPEG_SUPPORT preprocessor directives. If you don't know how to configure Visual Studio then you should use CMake as shown above since it will take care of everything automatically.
You have to download them, put them in your project directory, and then include them almost the same way you would do in python. You need to include only the .h files.
Example for test.h:
#include "test.h"
Hope this helps!
I have problem with installing OpenCV under Windows 7 x64. Following this. Downloaded executable and ran it. But I do not see any bin folder, instead there are 2 folders: build and source. What to do next I do not know, what to include to system path and how?
Note:
I am not using visual c++, instead I use devcpp editor.
The OpenCV windows installer comes as a self-extraction program. It essentially packs everything including the source files, docs, and most importantly, the pre-compiled files.
The pre-compiled files are located in build, and sources files are located in source. If you are intented to use opencv libraries solely, all you need to do is to
add build/include/ into your IDE additional include list.
selectively add build/lib/.. into the additional link list according to your vs version.
add build/bin/ to your system PATH, so your program can find them.
I downloaded cpptest from internet, and I want to build it using Visual Studio 2008.
The problem is that instead of .sln and vcproj file, Makefile.am is distributed, and I believe that all the all the necessary included file is included in the Makefile.am.
How to use Makefile.am to generate VS project files? I tried to use Cmake, but there is no CMakeList in the distribution.
Edit: Thanks to all the answers! There is a sln file distributed after all. But I am still interested to know the answer to my original question.
the visual studio project files for cpptest are in the win directory, not in the src directory where the makefile is..
edit
makefiles are meant to be used with GNU make. If you want that on windows, you can look at Mingw, GnuWin32 or Cygwin. But they also require gcc for compiling, so you won't really be using VS.
However, for most projects that do not have external dependencies it's no big deal if you do not have the VS project file: after all a makefile is just a list of the source files and some compilation options. To successfully build projects like cpptest, you could just create an emtpy VS project, add all source files to it, set output type to executable, build it and you're done. Eventually you can tune optimization options, but for the rest the default options will just do fine.
Go to win\VisualStudio.NET and you will find a VS solution file.
I just downloaded the archive and found the .sln file. It is under: /win/VisualStudio.NET. You can open that with VS2008 and update it, it should work.