I try to compile this small example and I have this error executing the make:
g++ -o ogl_cs_example main.cpp opengl_cs.cpp opengl_util.cpp -Wall -Iinclude -lX11 -lGL -lGLU
/tmp/ccFLIOt2.o: In function `updateTex(int)':
main.cpp:(.text+0xc6): undefined reference to `glDispatchCompute'
/tmp/ccQ8pShN.o: In function `genTexture()':
opengl_util.cpp:(.text+0x3df): undefined reference to `glBindImageTexture'
/tmp/ccQ8pShN.o: In function `initGL()':
opengl_util.cpp:(.text+0x7dd): undefined reference to `glXCreateContextAttribsARB'
collect2: error: ld returned 1 exit status
make: *** [example] Error 1
What am I missing?
Those functions are all OpenGL / GLX extensions that are not provided by your platform's minimal implementation.
You have to load them at run-time using glXGetProcAddress (...), they are not contained in any library that you link directly to. Though you can link to an extension managing library such as GLEW to do the dirty work for you, you will still have to do more than merely add a new linking dependency.
You generally have to initialize said libraries after you create your OpenGL render context. It is worth pointing out that one thing that sets WGL (Windows) and GLX (X11) apart is that you do not have to create a GL context before you can load extensions with GLX, so you can actually load glXCreateContextAttribsARB, glDispatchCompute and glBindImageTexture before you have a context. Whether the later two function pointers you get will do anything at run-time is a different story, however, and depends on the capabilities of the context you created.
You are forgetting to link something. If you are using GLEW, make sure you are linking to glew32.lib (or libglew32.a or whatever for your system).
undefined reference means you did not LINK to the libraries
Related
I have installed the GMP library and try to cross-compile with mingw-w64-posix.
My Library is in /usr/local/lib.
My compile command looks like the following:
x86_64-w64-mingw32-g++-posix src/factorial.cpp -o bin/factorial.win.o -I/usr/local/include -L/usr/local/lib -lgmp -lgmpxx
It throws an undefined reference error:
(I can remove the whole block from -L...., same error. Seems like the library doesnt link for some reason)
/usr/bin/x86_64-w64-mingw32-ld: /tmp/ccxY03WS.o:factorial.cpp:(.text$_ZN23__gmp_binary_multiplies4evalEP12__mpz_structPKS0_S3_[_ZN23__gmp_binary_multiplies4evalEP12__mpz_structPKS0_S3_]+0x27): undefined reference to `__gmpz_mul'
/usr/bin/x86_64-w64-mingw32-ld: /tmp/ccxY03WS.o:factorial.cpp:(.text$_ZN23__gmp_binary_multiplies4evalEP12__mpz_structPKS0_l[_ZN23__gmp_binary_multiplies4evalEP12__mpz_structPKS0_l]+0x26): undefined reference to `__gmpz_mul_si'
/usr/bin/x86_64-w64-mingw32-ld: /tmp/ccxY03WS.o:factorial.cpp:(.text$_ZN10__gmp_exprIA1_12__mpz_structS1_E7init_siEl[_ZN10__gmp_exprIA1_12__mpz_structS1_E7init_siEl]+0x1a): undefined reference to `__gmpz_init_set_si'
/usr/bin/x86_64-w64-mingw32-ld: /tmp/ccxY03WS.o:factorial.cpp:(.text$_ZN10__gmp_exprIA1_12__mpz_structS1_EC1EOS2_[_ZN10__gmp_exprIA1_12__mpz_structS1_EC1EOS2_]+0x2e): undefined reference to `__gmpz_init'
/usr/bin/x86_64-w64-mingw32-ld: /tmp/ccxY03WS.o:factorial.cpp:(.text$_ZN10__gmp_exprIA1_12__mpz_structS1_ED1Ev[_ZN10__gmp_exprIA1_12__mpz_structS1_ED1Ev]+0x14): undefined reference to `__gmpz_clear'
collect2: error: ld returned 1 exit status
However if i change my compiler to g++ instead everything works fine.
OK -
The link errors (__gmpz_init, __gmpz_clear, etc.) are GMP "internals". They're supposed to come from libgmp, the C-language base library.
The code that's referencing them (.text$ZN23__gmp_binary_multiplies4evalEP12__mpz_structPKS0_S3[ZN23__gmp_binary_multiplies4evalEP12__mpz_structPKS0_S3], etc.) is "name mangled" C++.
I suspect the problem is that your "gmpxx" library was built with a different C++ compiler, that has a different "name mangling" convention than MinGW.
SOLUTION:
Download the complete libGMP source (e.g. from https://gmplib.org/, and rebuild EVERYTHING (including libgmpxx) with your libmingw-w64-posix++ C++ cross-compiler.
ADDENDUM:
I downloaded gmp-6.2.1 source, and found __gmpz_clear here:
gmp-6.2.1\gmp-h.in
#define mpz_clear __gmpz_clear
__GMP_DECLSPEC void mpz_clear (mpz_ptr);
"gmp-h.in" is a template used by the project's "autoconf", to generate the libGMP source files for the specified target environment.
Which, in turn, means:
The project you started out with (in your original question) wasn't configured for MinGW
... and ...
You didn't run "configure" correctly when you tried building from source.
SUGGESTION:
Try building libGMP from source again. DELETE everything, re-extract from the libGMP tarball, and carefully follow the INSTALL instructions:
./configure
make
make check <= VERY IMPORTANT!!
make install
I'm curious about your build environment (Windows? Linux?), compiler (exact MinGW version) and target (if you're building on a Windows workstation, do you want to run your GMP app as a Windows .exe)?
I have a cpp code in which I have included tcl.h library. I am trying to compile it using the gcc compiler. but I'm getting the following error :
gcc -o top.o -std=c99 top.c
top.c:12: warning: return type defaults to 'int'
/tmp/ccDOTTZQ.o: In function `main':
top.c:(.text+0xa): undefined reference to `Tcl_CreateInterp'
top.c:(.text+0x1f): undefined reference to `Tcl_EvalFile'
top.c:(.text+0x3d): undefined reference to `Tcl_GetVar2Ex'
top.c:(.text+0x75): undefined reference to `Tcl_ListObjGetElements'
top.c:(.text+0xb1): undefined reference to `Tcl_GetString'
top.c:(.text+0xcc): undefined reference to `Tcl_GetInt'
collect2: ld returned 1 exit status
Its not able to find the Cpp-tcl APIs. Kindly help me with this.
Your code is not linking to the Tcl library, so obviously it can't find the implementations of those functions. (In C and C++, the linking to the implementations of functions is a separate stage from the use of the declarations of those functions, which is what the header files provide.)
Except that you're actually calling gcc wrong. You need to use two steps, first with -c to compile the source code to an object file:
gcc -c -o top.o -std=c99 top.c
Then like this to link the result and make an executable:
gcc -o top.exe -std=c99 top.o -ltcl
With the first, you might need to additionally specify an appropriate -I option to locate the include files (if they're not in the standard locations). With the second, you might need to specify an appropriate -L option to locate the library files (libtcl.so). Depending on the system, you might also need to specify some version numbers (e.g., -ltcl86 or -ltcl8.6 instead of -ltcl). These are all options that depend on your build system configuration, so they're hard to predict exactly here.
Until some weeks ago, using the boost_regex library I used to compile a C++ file test.cpp using the following command.
g++-4.9 -Wall -O3 -march=native -flto -DNDEBUG -o test \
--std=c++14 test.cpp -lboost_regex -pthread
The compilation was working perfectly. But at some point, I needed to upgrade my OS (more precisely, it was Ubuntu 14.04, now it is Ubuntu 16.04).
I kept my local folders with my data, and I also installed the Boost library again in the new system, including boost_regex.
The Boost version in the new system is 1.58, unfortunately I cannot know which Boost version I was using before because it is now deleted.
I try to compile again the same file in the new system, with the same command as above, and the linker says it cannot find two functions called maybe_assign and construct_init. If I replace the -o test option with just -c (i.e. without linking) then the program is compiled without errors.
More precisely, when I try to do linking I get the following errors (they were extremely long, I hade to shorten using ... dots).
In function `boost::re_detail::perl_matcher<...>::match_match()':
undefined reference to `boost::match_results<...>::maybe_assign(boost::match_results<...> const&)'
In function `bool boost::regex_search<...>(...)':
undefined reference to `boost::re_detail::perl_matcher<...>::construct_init(...)'
In function `boost::re_detail::perl_matcher<...>::match_prefix()':
undefined reference to `boost::match_results<...>::maybe_assign(boost::match_results<...> const&)'
collect2: error: ld returned 1 exit status
I really don't know how this is possible, the libraries seem perfectly installed, nothing seems missing, and the compilation was working with a previous OS installation (then I guess older libraries).
At these point my only guess could be that Boost authors removed such functions? (maybe they are obsolete?). But I didn't find any trace of this on internet. If this is the case, how can I know the boost versions in which such functions are available?
Am I doing any mistake? Do you have any suggestions to investigate about this?
TL;DR use gcc5.
Ununtu 16.04 comes with gcc5 by default. Every C++ library in it is compiled with that compiler.
Now there was an incompatible C++ ABI change between gcc4 and gcc5. It made binaries built from C++ sources with gcc4 incompatible by default with binaries built with gcc5. This incompatibility often manifests itself as a bunch of undefined symbols that reference std::string and/or std::list.
The standard library comes built with a dual ABI to support objects built with older compilers. Other libraries like boost, hovever, don't.
I'm trying to build a C++ program that incorporates Cepstral's voice synthesis features. The library was already downloaded on the machine by my predecessor but apparently he never got around to using it. The documentation is pretty much non-existent (there is a single forum that doesn't really have anything helpful). All of their included examples are in C and lack a MakeFile so I'm trying to compile them myself. The little documentation there is simply tells me I need to link to the libswift.so library.
It is a Ubuntu 12.04.5 OS and I tried this compile command
g++ -Wall -g tts.c -o tts -I/opt/swift/include -L/opt/swift/lib -lswift -lm
Which gives this error
/opt/swift/lib/libswift.so: undefined reference to 'sin'
/opt/swift/lib/libswift.so: undefined reference to 'exp'
/opt/swift/lib/libswift.so: undefined reference to 'cos'
/opt/swift/lib/libswift.so: undefined reference to 'log'
/opt/swift/lib/libswift.so: undefined reference to 'pow'
collect2: ld returned 1 exit status
This seems to indicate that -lm is not properly linking for some reason (I also tried switching the order of m and swift for the same result).
I usually use C++ and have very little C experience. I also frequently use Makefiles or edit previous/provided Makefiles and rarely call g++ itself so it's possible I'm missing something fairly obvious. Thanks.
This question already has answers here:
What is an undefined reference/unresolved external symbol error and how do I fix it?
(39 answers)
Closed 7 years ago.
I was trying to use glew32.lib file to link in my project, than I compile Glew source by myself to get glew.a file. Now, I have these link errors in my project:
g++ -o Chapter10(OpenCLTest).exe src\Chapter10(OpenCLTest).o -lopengl32 -lglew -lglut32 -lglu32 -lopencl
src\Chapter10(OpenCLTest).o:Chapter10(OpenCLTest).cpp:(.text+0x167): undefined reference to `_imp____glewBindBuffer'
src\Chapter10(OpenCLTest).o:Chapter10(OpenCLTest).cpp:(.text+0x39a): undefined reference to `_imp__glewInit'
src\Chapter10(OpenCLTest).o:Chapter10(OpenCLTest).cpp:(.text+0x3a7): undefined reference to `_imp__glewIsSupported'
src\Chapter10(OpenCLTest).o:Chapter10(OpenCLTest).cpp:(.text+0x48a): undefined reference to `_imp____glewGenBuffers'
src\Chapter10(OpenCLTest).o:Chapter10(OpenCLTest).cpp:(.text+0x495): undefined reference to `_imp____glewBindBuffer'
src\Chapter10(OpenCLTest).o:Chapter10(OpenCLTest).cpp:(.text+0x4dd): undefined reference to `_imp____glewBufferData'
src\Chapter10(OpenCLTest).o:Chapter10(OpenCLTest).cpp:(.text+0x50b): undefined reference to `_imp____glewGetBufferParameteriv'
src\Chapter10(OpenCLTest).o:Chapter10(OpenCLTest).cpp:(.text+0x1d67): undefined reference to `_imp____glewBindBuffer'
src\Chapter10(OpenCLTest).o:Chapter10(OpenCLTest).cpp:(.text+0x1d7f): undefined reference to `_imp____glewDeleteBuffers'
src\Chapter10(OpenCLTest).o:Chapter10(OpenCLTest).cpp:(.text+0x1d95): undefined reference to `_imp____glewBindBuffer'
src\Chapter10(OpenCLTest).o:Chapter10(OpenCLTest).cpp:(.text+0x1dad): undefined reference to `_imp____glewDeleteBuffers'
src\Chapter10(OpenCLTest).o:Chapter10(OpenCLTest).cpp:(.text+0x2078): undefined reference to `_imp____glewBindBuffer'
collect2: ld returned 1 exit status
It is good to solve this problem but by the way I want to ask are there any other opengl implementaions of gl extentions?
I'm afraid you can't use glew.lib with g++ (because .lib is a proprietary Microsoft format). These errors you get are missing function entry points, meaning that you didn't compile GLEW correctly (the required functions are not exported in your .so - need to know more details in order to be able to solve this issue).
As for the other part of the question, you can try GLEH. It is still in the development phase and may need some tweaking to work for you, but we've been using it quite successfuly in linux so it shouldn't be too bad.
(I know this is a bit late, but I figured it might solve someone else's problem, so) I had a very similar problem compiling a program that linked to GLEW dynamically. It turns out that I had overlooked the libglew32.dll.a file - that also needed to be present (in addition to libglew32.a and glew32.dll that I had previously copied to my project folder.)
You could try GLee which essentially does the same thing as GLEW.
Strange nobody has said anything about this. By default on Windows, the GLEW headers use declspec(dllimport) for all of the external functions, which mangles all of their names. This is why all of the missing external symbol names all have _imp____ at the front.
If you wan't to use a static build of GLEW (you mentioned something about libglew.a), define GLEW_STATIC during the build of GLEW and during the build of your application. This will unmangle the names for static linking.
If you want to link to a shared library version of GLEW, make sure to build GLEW with GLEW_BUILD. I'm not sure if this is necessary with gcc but it is if the library is built with MSVC.
Furthermore, the GNU toolchain actually supports Microsoft's .lib format for linking. source
You may find it easiest to just compile GLEW yourself or even include it in your project. It is only one source file and a few headers. To compile the library manually, use something along the lines of gcc -shared -o libGLEW.dll -Wl,--out-implib=libGLEW.dll.a -O2 -DGLEW_BUILD glew.c. To get the static version use something like gcc -c -O2 -DGLEW_STATIC glew.c instead.