I have been referring to https://learnopengl.com/. In those tutorials, many libraries were used for performing different tasks. I have worked on those tutorials on Windows 7 in Visual Studio 2013, linking all the .lib files and .dll files correctly for that project inside Visual Studio 2013.
But now the issue is that I want to run the program from command line. But I can't run, since none of the libraries and header files are linked and I get various errors saying Couldn't locate filename and unresolved name in function.
Any ideas how do I link the libraries and header files so that I can run the program from command line?
I know this can be marked as an open ended and not clear question, but I am stuck and all the answers which I have gone through did not describe clearly about linking the .lib files?
As #Michael Chourdakis suggested, msbuild was the thing I was looking for.
Related
Situation
I learned a lot over the last year, but this is something I just could not wrap my head around. Project is C++. CMake 1.15.2. Visual Studio 2015.
I converted a whole Solution *.sln file with cmake-converter and wrote FindXXX.cmake Modules for all external *.libs defined in the *.vcxproj files.
Everytime I encountered an error: unresolved external I added the corresponding Target Sometarget::somecomponent to the target_link_libraries(ConsumingTarget ... ) call.
Now I have a build that works and produces no errors. Some executables say something along the lines of:
"Execution of code cannot be continued because somecomponent.dll is not found..."
I have
An original .sln file that produces executables only requiring .lib files
A CMake generated .sln file that produces executables requiring .dll files
Working FindXXX.cmake files which add_library(XXX::yyy UNKNOWN IMPORTED)
They find the headers and the .lib files (.dll files are not existing/intended/needed in the original VS .sln)
They create the corresponding Targets for all .lib files
Consuming Targets which target_link_libraries(ConsumingTarget PRIVATE XXX::yyy)
"A working build"
An error "before starting the main function".
What I have tried
I have tried defining an OBJECT Library and adding this to the sources of ConsumingTarget and removing Sometarget::somecomponent from the target_link_libraries call. CMake Doc on Object Libraries
I have tried reading and understanding the difference between module and library. Even the CMake documentation on imported Libraries couldn't help me understand my problem.
I have tried reading and understanding the difference between linking a static and shared library.
My Assumptions
Adding the imported library is done wrong by me.
Reason: DependenciesGui.exe shows different dependencies for the cmake-generated-executable and the original-sln-executable but the linker calls (shown in VisualStudio 2015) seem to be the same.
Whole Program Optimization in the CMake File does not work the same way it does in the original .sln file although the Flags are activated at all levels described in this answer.
Reason: compiling with the original file I noticed warning C4505: 'foobar': unreferenced local function has been removed - I don't seem to get those warnings with the cmake-generated build.
subassumption: Functions which won't be called are optimized away, thus removing the necessity for the .dll file.
I expect/hope for
ConsumingTarget.exe to run without asking for somecomponent.dll
another explanation on imported targets and how to link libraries where .dlls should not be necessary.
an explanation on how to analyze/compare the two binaries regarding their symbols(?) and map the seen information to CMake commands. (I am using DependenciesGui.exe to look for dependencies in the .exe file)
Possible reason for failure
One executable had no /DELAYLOAD... directive after conversion with cmake-converter. Opened Issue. Question Title still holds.
Edits:
1: Added possible reason for failure
I'm trying to use this library: https://github.com/micknoise/Maximilian to do some DSP and am pretty new to C++ compilation which is leading me to some issues,
I'm using Visual Studio 15 and have successfully included a number of statically linked libraries that come in .lib and .a form but am confused on how to link the aforementioned code into my project since it does not come in a compiled form. Simply putting the unzipped project folder (which contains maximilian.h and then a /lib directory with the rest of the .c and .h files) into my include paths leads to linker errors. Am I missing a step?
Thanks to the help above, I was able to get the .lib file by opening the visual studio project and changing the export from .exe to .lib. I then included that in my project and things worked great.
I am using boost generic image library and it requires libpng. I built libpng and obtained the files libpng.lib, zlib.lib and libpngd.lib. When I tried to compile my project, Visual Studio gives a fatal error
fatal error LNK1120: 21 unresolved externals
with a bunch of unresolved external symbols like _png_set_sig_bytes and _png_read_row. What's going on here and how to solve it?
From MSDN:
https://msdn.microsoft.com/en-us/library/ba1z7822.aspx?f=255&MSPPError=-2147217396
To add .lib files as linker input in the development environment
Open the project's Property Pages dialog box. For details, see Setting Visual C++ Project Properties.
Click the Linker folder.
Click the Input property page.
Modify the Additional Dependencies property.
You must do this; explicitly specifying "libpng.lib", "zlib.lib" and "libpngd.lib" in your .exe's link command.
So this is coming from a complete simple minded moron so maybe this'll be helpful....it took me a little while to grasp. Basically, you're downloading the source code. That means, that you have to be the one to compile the source code.
Windows can compile programs that are written in C in the command prompt. You have to build the program, and it spits out a .dll or a .lib file. That or those are the files that you link to visual studio application.
You set dependencies to the header files which is usually like the source codes root folder or wherever all those .h files are.
You then set the linker to link to the .dll or .lib file(s). In Boost C++'s case, you need to link to a 'lib' folder.
I think what you need is to go over and completely grasp the basics. Here's a link from Microsoft on how Windows can compile C programs from the command prompt:
https://learn.microsoft.com/en-us/cpp/build/walkthrough-compile-a-c-program-on-the-command-line?view=vs-2019
I am trying to use OpenCv in Visual Studio 2012. I followed every single step this question has provided and every other that can be found on the internet. I even tried to work with different versions of opencv but the error didn't go away.
The error is:
error LNK1104: cannot open file 'opencv_calib3d230d.obj'
All the required libraries are included in linker configurations of visual Studio. Envoirnmental variable "Path" has also been updated but still the error is there.
What can I do to solve this problem?
I have search for calib3d230d.obj every where but it is not inside the extracted folder.
I downloaded OpenCv superpack.exe from HERE
Regards
Firstly, you should be linking to .lib files, opencv does not normally include any .obj files. Change this in your linker dependencies. Secondly, do you definitely have the debug version of the libraries? If not, then you need to specify the static libraries without the d on the end of the name (opencv_calib3d230d.lib -> opencv_calib3d230.lib).
I encountered the same problem before. Finally I found that I forgot to type ".lib" after the library file in vc++ linker.
Wish this can help you.
I am trying to find a good way to determine what module at link time is causing a certain library to get processed as a "/DEFAULTLIB" as seen in the verbose linker output from Visual Studio.
Here is my situation, I have several static library pre-requisites and each has a release and a debug version (BlahD.lib and Blah.lib). For some reason at link time all of the *D.lib's are processed as default libraries even though I am building a release with the non-debug libs specified as "Additional Dependencies". If I never build the debug versions of the static libraries those *D files wouldn't exist and there would be a linker error (can't open file).
I can get my project to build successfully by specifying /NODEFAULTLIB for all of these offending .lib files. All the release libraries link up and everyone is happy. But I want to understand what is going on here. What is causing these *D.lib files to be processed by the linker? Is my only hope to write some kind of script that dumpbins everything in this massive project and its dependant projects (microsoft support)? Even then I don't understand what to look for in the dumpbin output, does this apply to the .lib files as well the .obj files?
I had a similar problem. I was only able to solve it by analyzing the *.obj files as you suggested. To do it, I ran the following command via the Visual Studio command prompt (in the temp folder of the project, where *.obj files are generated):
for /R %1 in (*.obj) do #dumpbin /directives /section:.drectve "%1" > "%1".directives.txt
Then I used Notepad++ to search for the name of the offending library in all of these *.directives.txt files. This revealed which project was referencing the wrong lib.
Note: you may want to modify this to include any 3rd-party *.lib files your project may use, and not just *.obj files. "/DEFAULTLIB" directives may also come from them.
Note: you may need to use *.o instead of *.obj
Look for #pragma comment(lib) in the source. See if it perhaps is dependent on a #define - This is a common way for a SDK to ensure that the right libs are linked, and you may need to define THESDK_DEBUG or THESDK_RELEASE for the logic to work out.
Additional information:
I discovered in Visual Studio 2008 that even commenting out the statement from the *.idl file does not work, as in:
//cpp_quote("#pragma comment( lib, \"MYLIB.lib\")")
The compiler still adds MYLIB.lib as a DEFAULTLIB, and it winds up in the *.obj file. Make sure you remove the line completely from the code!
Link with the /verbose option and search the output for the name of the library in question. This will tell you which object file dragged the library into the link.