I am facing issues with the C++ cUrl Library on Windows, using Visual Studio 2012.
I have a CGI project which generates a .cgi file. This project includes another project called Library which is a Static Library Project.
In the Library project, I have the code which uses cUrl and includes curl/curl.h. I have referenced the Preprocessor Definition CURL_STATICLIB.
Then in my CGI Project, I have linked libcurl.lib to my project in Configuration Properties > Linker > Additional Dependencies.
But when I try to build the Solution, I still have those errors :
error LNK2001: unresolved external symbol _curl_easy_setopt in Library.lib(fct_util.obj)
error LNK2001: unresolved external symbol _curl_easy_perform in Library.lib(fct_util.obj)
error LNK2001: unresolved external symbol _curl_easy_init in Library.lib(fct_util.obj)
error LNK2001: unresolved external symbol _curl_easy_cleanup in Library.lib(fct_util.obj)
I already took a look at this topic : Unresolved symbols when linking a program using libcurl, as well as other related topics but couldn't find a solution for my problem.
Am I missing something ?
Kind Regards.
Credit to this guy helped me get further than any docs.
Still have a couple more issues.
https://www.youtube.com/watch?v=wjNyT5PhNvI
Then do this , someone in the video comments
Very important after you do everything in video.
Need to navigate back to solution right click properties
(see below comment)
"Thanks , it worked after i added Normaliz.lib;Ws2_32.lib;Wldap32.lib;Crypt32.lib;advapi32.lib in Additional Dependencies(property->linker->input)"
Related
I am trying to build the tensorflow C++ API (version 1.15.0, under Windows). I have managed to do so (after manually exporting some functions), but when used in the project I get the linker errors which are caused by the protobuf generated files config.pb.h located in the core include folders within TF.
error LNK2001: unresolved external symbol "const tensorflow::ConfigProto::`vftable'" (??_7ConfigProto#tensorflow##6B#)
error LNK2001: unresolved external symbol "const tensorflow::RunOptions::`vftable'" (??_7RunOptions#tensorflow##6B#)
This can't be resolved by manually adjusting the code before the lib is being built (as far as I know). Am I missing something obvious?
I am developing windows program, and got link error :
error LNK2001: unresolved external symbol __imp__wcsicmp
error LNK2001: unresolved external symbol __imp_fputws
error LNK2001: unresolved external symbol __imp_towupper
It seems like I need wide char version fputs() and toupper(), but I can't find it.
Could someone provide the library name or compile settings that will resolve the link error?
Environment : Win server 2008 + visual studio 2010 pro + WinDDK 7600.16385.1
Not sure if it was the case for you, but I was using the (lib file) meant for a MD runtime execution instead of a MT runtime execution.
Using the correct lib in:
Project Properties -> Configuration Properties -> Linker -> Input -> Additional Dependencies
helped me fix the issue
I'm in the process of converting 32bit project to x64. In most cases it just means appending 64 to library paths (and eventually building those libraries for x64). Now I assume all libraries are already ready and the code is also x64 compatible. But I keep getting errors for boost zlib library, like these:
error LNK2019: unresolved external symbol inflateEnd
error LNK2019: unresolved external symbol inflate
error LNK2019: unresolved external symbol inflateInit_
error LNK2019: unresolved external symbol deflateEnd
error LNK2019: unresolved external symbol deflate
error LNK2001: unresolved external symbol "int const boost::iostreams::zlib::default_compression"
error LNK2001: unresolved external symbol "int const boost::iostreams::zlib::deflated"
error LNK2001: unresolved external symbol "int const boost::iostreams::zlib::default_strategy"
I enabled verbose mode for linker (in MS Visual Studio you do this by adding /VERBOSE:LIB to additional linker options). Thanks to that, I can see this output line:
Searching .\..\..\libs\boost145\stage\lib64\libboost_zlib-vc100-mt-gd-1_45.lib
That would imply that the library was found in the boost145\stage\lib64. So what should I be looking for now?
One strange thing is that file that defines the first group of missing symbols (those that are not within boost) has header files within the project, zlib.h and zconf.h. Maybe this is some hint? The zlib.h defines external symbols as:
ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
Obvious question is: where the hell is lib file for this header file?
I had the same issue, to resolve the errors I download the source from zlib and built the x64 dlls/libs locally. There were a couple issues with solution file downloaded, fixes are described below.
Zlib 1.2.8 source code: http://zlib.net/zlib128.zip
Solution File for VS2012 is located at: zlib-1.2.8\contrib\vstudio\vc11\zlibvc.sln
Fixes:
Change:
<Command>cd ..\..\..\contrib\masmx64
bld_ml64.bat</Command>
to:
<Command>cd ..\..\contrib\masmx64
bld_ml64.bat</Command>
In zlibvc project properties -> Linker -> Advanced -> Image Has Safe Exception Handlers -> set to No (/SAFESEH:NO). Info about SAFESEH: Compiling libffi with VS2012 fails with fatal error LNK1281: Unable to generate SAFESEH image
We have a project which is an executable, which loads DLL files at run time as plugins.
We're trying to make a new plug in which has many library dependencies, and some of those dependencies are the same library but different versions that other plugins link to.
Because the libraries are depended on by different plugins at different versions, I would like to statically link/build any dependencies into the new plugin - that way they can't conflict with the old plugin dependencies. As far as I know, nothing in the dependencies of the plugin need to be exported, they're just used by the plugin.
Is it possible to do this?
I've tried building all the static libs in visual studio as static libraries with the runtime set to Multithreaded DLL with the /MD flag, but when I try to build dynamiclibB.dll, I get linker errors. If I set dynamiclibB to build as a static library, it doesn't have the linker errors.
I haven't tried linking newplugin.dll to the static library version of dynamiclibB yet, but I think I have exactly the same situation, so I see no reason why it would work there where it doesn't one level down.
I don't want to build dynamiclibB as a static library anyway, as it would be good to be able to update newplugin.dll without including dynamiclibB.dll if it hasn't been changed, as in, to decouple the update process. This line of reasoning would suggest that I should have .dlls for everything, but the conflicts of versions is what worries me, I think.
I cannot build the plugins as static libraries as they need to be loaded at run time.
Absolutely everything is being built in release mode for now, to avoid that complication.
What am I missing?
An attempt at a diagram that might help understand the situation:
program.exe
|
________________
| |
oldplugin.dll newplugin.dll
| |
dynamiclibA.dll dynamiclibB.dll
|
_________________________
| | |
staticlibA.lib slibC.lib slibD.lib
Update:
Providing some more information now that I know what's happening, and know that more specific details are actually relevant.
So library A, represented by dynamiclibA and staticlibA was zlib.
The library we were compiling (dynamiclibB) for use in the newplugin was PoDoFo.
The error messages we got were:
Error 19 error LNK2001: unresolved external symbol
_deflateInit_ E:\Work\podofo_bin\src\PdfFiltersPrivate.obj podofo_shared Error 20 error LNK2001: unresolved external symbol
_inflateEnd E:\Work\podofo_bin\src\PdfFiltersPrivate.obj podofo_shared Error 21 error LNK2001: unresolved external symbol
_inflateEnd E:\Work\podofo_bin\src\libpng16.lib(pngread.obj) podofo_shared Error 22 error LNK2001: unresolved external symbol
_deflate E:\Work\podofo_bin\src\PdfFiltersPrivate.obj podofo_shared Error 23 error LNK2001: unresolved external symbol
_deflate E:\Work\podofo_bin\src\libpng16.lib(pngwutil.obj) podofo_shared Error 24 error LNK2001: unresolved external symbol
_deflateEnd E:\Work\podofo_bin\src\PdfFiltersPrivate.obj podofo_shared Error 25 error LNK2001: unresolved external symbol
_deflateEnd E:\Work\podofo_bin\src\libpng16.lib(pngwrite.obj) podofo_shared Error 26 error LNK2001: unresolved external symbol
_inflateInit_ E:\Work\podofo_bin\src\PdfFiltersPrivate.obj podofo_shared Error 27 error LNK2001: unresolved external symbol
_inflateInit_ E:\Work\podofo_bin\src\libpng16.lib(pngrutil.obj) podofo_shared Error 28 error LNK2001: unresolved external symbol
_inflate E:\Work\podofo_bin\src\PdfFiltersPrivate.obj podofo_shared Error 29 error LNK2001: unresolved external symbol
_inflate E:\Work\podofo_bin\src\libpng16.lib(pngrutil.obj) podofo_shared
Putting the rest in an answer.
In my question, slibc.lib was libpng. Libpng also requires zlib, but it builds it from source inside its solution. We were able to use the output of that project in the way we desired, as in, zlib.lib built with /MD flag, without linking errors.
We've also managed to work out why this problem occurred:
another stackoverflow question was very relevant: https://stackoverflow.com/a/6559315/78823
Turns out that zlib has a #define ZLIB_WINAPI which defined the call convention to be STDCALL, which I don't understand, but it caused the linker errors. The other answer suggests to remove the define, and I suppose that's what libpng did with its zlib project.
I'm guessing that the reason why the linker errors only occurred when building the .dll and disappeared when building the .lib is because (correct me if I'm wrong, I don't fully understand this), build a .lib doesn't actually do the linking to the required functions, so would have been just passing on the linker errors to the next level up; I think we would have seen the same errors (but in different objs/projects perhaps) when compiling newplugin.dll, but we didn't get far enough to check that before we tried other things.
This is my situation (I am very new to C++ MFC coding and I am trying to debug an existing application project)
I use this line in my code (in a visual studio 2012 MFC project)
CoCreateInstance(CLSID_PortableDeviceValues, NULL,
CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&x));
While I run the project, i get a linker error like this
error LNK2001: unresolved external symbol _CLSID_PortableDeviceValues
This happens for all the CLSID values that I am referring to in the code. Like this
error LNK2001: unresolved external symbol
_CLSID_PortableDeviceKeyCollection
error LNK2001: unresolved external symbol _IID_IPortableDeviceEventCallback
error LNK2001: unresolved external symbol _CLSID_PortableDeviceManager
error LNK2001: unresolved external symbol _CLSID_PortableDeviceServiceFTM
I checked for the declaration of "CLSID_PortableDeviceValues" and it was found in "PortableDeviceTypes.h" and I have imported that library as well.
I do not get any compiler error, but run into the linker errors mentioned above..
Can someone please help me out here. I could not resolve this ..
You will need to add PortableDeviceGUIDs.lib to your project.
(Look up the section "Requirements" in the MSDN documentation for IPortableDeviceValues)
When the linker builds your project, it is looking for the implementation data that is behind the identifier CLSID_PortableDeviceValues. This data is in the library PortableDeviceGUIDs.lib, and the linker has to be told to use this library.
The header file you included in your source code only declares the symbol "CLSID_PortableDeviceValues", without importing its implementation.