Getting undefined reference to 'clock_gettime' error, for curl program - c

Gretings,
I have cross compile, OpenSSl , libssh2 and finally cURL, Don't know why it has generated only static library. Anyway I tried to run sample ftpget.c program by linking all the three libraries but I am getting the following error :
.../libcurl.a(timeval.o): In function 'curlx_tvnow':
timeval.c:(.text+0xfc): undefined reference to 'clock_gettime'
collect2: ld return 1 exit status
make: *** [all] Error 1
Please help me resolve this error, Is there need to cross-compile any other library also ?
Thanks,
Yuvi

Try linking with librt (-lrt).

You need to link with the real-time library.
Use -lrt
gcc ... -lrt ...

Related

make doesn't link math lib when compiling

I get the following error while compiling xpdf using make. I've tried using the command:
LIBS=-lm make
However, it doesn't work. I know the problem is that the c compiler cannot recognise the math symbols in the source code because the math library is not available to it, but I don't know how to fix it.
[ 71%] Linking CXX executable pdftohtml
/usr/bin/ld: CMakeFiles/xpdf_objs.dir/Gfx.cc.o: undefined reference to symbol 'acos##GLIBC_2.2.5'
//usr/lib64/libm.so.6: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
make[2]: *** [xpdf/CMakeFiles/pdftohtml.dir/build.make:219: xpdf/pdftohtml] Error 1
make[1]: *** [CMakeFiles/Makefile2:428: xpdf/CMakeFiles/pdftohtml.dir/all] Error 2
make: *** [Makefile:130: all] Error 2
I have put my Makefile and makeLists.txt on pastebin for more information
I realised I had to use the g++ compiler instead of gcc after reading the man page for gcc which stated:
The usual way to run GCC is to run the executable called gcc, or
machine-gcc when cross-compiling, or machine-gcc-version to run a
specific
version of GCC. When you compile C++ programs, you should invoke GCC as g++ instead.

getting error when i compile c program through putty

/tmp/ccfg3L9u.o: In function `main':
Allgo-API-Test.c:(.text+0x968): undefined reference to `mport_get_sub_metadata_entries'
Allgo-API-Test.c:(.text+0xb24): undefined reference to `mport_set_play_scope'
collect2: error: ld returned 1 exit status
Makefile:86: recipe for target 'bin/MediaPort.elf' failed
make: *** [bin/MediaPort.elf] Error 1
I think you miss to link additional library while compiling file Allgo-API-Test.c
Before compiling this file you should have library which contain definition of mport_get_sub_metadata_entries and mport_set_play_scope. Once you get that library you can use below command to compile.
g++ Allgo-API-Test.c -l(your library) [-L(path to your library)]

OpenGL Compilation Errors Ubuntu

I'm trying to set up the code from
http://www.openglsuperbible.com/example-code/
with command:
$ cmake -G "Unix Makefiles" ; make clean ; make all
I've installed the following packages in order to prepare the system:
xrandr libxrandr x11-xserver-utils libxrandr-dev libglfw2 libglfw-dev xorg-dev libx11-dev libgl-dev libglu-dev libgl1-mesa-dev freeglut3 freeglut3-dev mesa-common-dev freeglut3-dev build-essential libx11-dev libx11-*
I may have missed some of the packages I've installed in this list, I apologize.
Then I've modified the CMakeList.txt in order to add to the linking phase the following things:
glfw GL rt glut X11 dl Xrandr Xext GLEW GLU
Then I try to compile, but it fails at the linking phase:
/opt/sb6code/src/xraw/xraw.c: In function ‘CreateWindow’:
/opt/sb6code/src/xraw/xraw.c:106:14: warning: assignment makes pointer from integer without a cast [enabled by default]
Linking C executable bin/xraw
CMakeFiles/xraw.dir/src/xraw/xraw.c.o:xraw.c:function CreateWindow: error: undefined reference to 'XOpenDisplay'
CMakeFiles/xraw.dir/src/xraw/xraw.c.o:xraw.c:function CreateWindow: error: undefined reference to 'XCloseDisplay'
CMakeFiles/xraw.dir/src/xraw/xraw.c.o:xraw.c:function CreateWindow: error: undefined reference to 'XCreateColormap'
CMakeFiles/xraw.dir/src/xraw/xraw.c.o:xraw.c:function CreateWindow: error: undefined reference to 'XCreateWindow'
CMakeFiles/xraw.dir/src/xraw/xraw.c.o:xraw.c:function CreateWindow: error: undefined reference to 'XMapWindow'
CMakeFiles/xraw.dir/src/xraw/xraw.c.o:xraw.c:function CreateWindow: error: undefined reference to 'glXCreateContextAttribsARB'
CMakeFiles/xraw.dir/src/xraw/xraw.c.o:xraw.c:function Cleanup: error: undefined reference to 'XDestroyWindow'
CMakeFiles/xraw.dir/src/xraw/xraw.c.o:xraw.c:function Cleanup: error: undefined reference to 'XCloseDisplay'
CMakeFiles/xraw.dir/src/xraw/xraw.c.o:xraw.c:function main: error: undefined reference to 'XNextEvent'
CMakeFiles/xraw.dir/src/xraw/xraw.c.o:xraw.c:function main: error: undefined reference to 'XGetWindowAttributes'
collect2: error: ld returned 1 exit status
make[2]: *** [bin/xraw] Errore 1
make[1]: *** [CMakeFiles/xraw.dir/all] Errore 2
make: *** [all] Errore 2
Now, I've tried to search the web and even here on SO.com for solutions, but they keep telling me to link the libraries I've already added to the linking phase.. so I can't seem to make any more progress.
Do you happen to have some knowledge or hint that could help me?
Ok, stimulated by answers I've gone into CMakeFiles directory and looked for the configuration file that manages the compilation. I've found out that for some reasons it did miss some of the flags stated into the CMakeLists despite of my update.
So now the compilation line looks like:
/usr/bin/cc CMakeFiles/xraw.dir/src/xraw/xraw.c.o -o bin/xraw -L/opt/sb6code/lib -rdynamic -lGL -lglut -lGLU -lm -lX11 -ldl -lGLEW -lXrandr -lXext -lrt -lglfw -Wl,-rpath,/opt/sb6code/lib
And the errors have reduced to :
CMakeFiles/xraw.dir/src/xraw/xraw.c.o:xraw.c:function CreateWindow: error: undefined reference to 'glXCreateContextAttribsARB'
collect2: error: ld returned 1 exit status
make[2]: *** [bin/xraw] Errore 1
make[1]: *** [CMakeFiles/xraw.dir/all] Errore 2
make: *** [all] Errore 2
Other hints? :)
Side Note:
I've also installed CUDA libraries and under path
/usr/lib/nvidia-304/
I happen to have
alt_ld.so.conf libnvidia-ml.so.1
bin/ libnvidia-ml.so.304.88
ld.so.conf libnvidia-opencl.so.1
libcuda.so libnvidia-opencl.so.304.88
libcuda.so.1 libnvidia-tls.so.304.88
libcuda.so.304.88 libnvidia-wfb.so.1
libGL.so libnvidia-wfb.so.304.88
libGL.so.1 libOpenCL.so
libGL.so.304.88 libOpenCL.so.1
libnvcuvid.so libOpenCL.so.1.0
libnvcuvid.so.1 libOpenCL.so.1.0.0
libnvcuvid.so.304.88 libXvMCNVIDIA_dynamic.so.1
libnvidia-cfg.so libXvMCNVIDIA.so
libnvidia-cfg.so.1 libXvMCNVIDIA.so.1
libnvidia-cfg.so.304.88 libXvMCNVIDIA.so.304.88
libnvidia-compiler.so tls/
libnvidia-compiler.so.1 vdpau/
libnvidia-compiler.so.304.88 xorg/
libnvidia-glcore.so.304.88 XvMCConfig
libnvidia-ml.so
Which I would like to use since I'm not sure that my intel graphic card supports OpenGl 4.* which I shall use with the book, while the nvidia one supports 4.2.
I really can't find any good how to on the matter, the Book conveniently avoids to give installation instructions.
Temporary Solution:
I've found out that this is the only source file that does not work. Removing its files and CMakeList.txt configuration seems to be wise until someone finds out another solution.
Also, i had to use optirun to run the executables, in case other people with bumblebee/nvidia are wondering why their programs do not work.
You probably link the libraries in wrong order; all these symbols are defined in libX11.a; you should want to see what is the actual linking command line fed to GCC, and post it here.
Update now it means that you are statically trying to link against an API function that is not available in your libs (it is an optional extension and should be queried dynamically).

'undefined reference' errors when compiling against library

I added a third party library to my code and is getting errors like this when running make. Please help me understand this error.
(.text+0x9b4): undefined reference to `snd_strerror'
/home/bet/Tent/tun/app/Common/hl/lib/libGHAL.a(gfxhal.o): In function `GFX_create_region':
/home/bet/Tent/tun/app/Common/hl/src/GHAL/gfxhal.c:1141: undefined reference to `my_key_handler'
/home/bet/Tent/tun/app/Common/hal/src/GHAL/gfxhal.c:1141: undefined reference to `create_window'
collect2: ld returned 1 exit status
make[2]: *** [all] Error 1
make[2]: Leaving directory `/home/bet/Tent/tun/app/Common/c_app'
make[1]: *** [ctv_all] Error 2
make[1]: Leaving directory `/home/bet/Tent/tun/app/Common'
Those are Linking errors, which tell you the linker cannot find definitions for the library you are using.
You will have to link the library to your project.
gcc <your files for compilation> -lLibName
Read this for better understanding.
I still get the error even if
readline library is installed and
-lreadline is added to gcc compiling command.
The root cause of my issue is the order of the libraries/code: -lreadline (and other libraries) should be put right before -o options.

Program compiles on one server, doesn't on another

I'm getting this error when I try and compile my program on my school's external server.
Undefined first referenced
symbol in file
pow /var/tmp//ccWbipvM.o
sqrt /var/tmp//ccWbipvM.o
ld: fatal: Symbol referencing errors. No output written to assign1
collect2: ld returned 1 exit status
The problem is I don't get it when I compile it locally - it runs fine. Can anyone give me some advice as to what the problem is here?? Thanks!
PS: math.h has been included.
Try linking your program with the math library by using the -lm flag:
gcc -o prg -lm prg.c

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