I can include items from xcb/xcb.h, but not items that are outlined in /usr/include/xcb/randr.h.
My preference is to use C++, but to help debug I also tried C which produced variations of the same error.
I am certain I am doing something incorrectly, but I am not sure where to start looking to resolve this. Thank you very much for reading, any suggestions?
Example
main.cpp
#include <xcb/xcb.h>
#include <xcb/randr.h>
int main()
{
const xcb_setup_t * xsetup;
xcb_connection_t * conn;
xcb_screen_t * screen;
xcb_window_t root_win;
xcb_screen_iterator_t screen_iterator;
xcb_randr_get_screen_resources_cookie_t resources;
// connect to Xserver
conn = xcb_connect(NULL, NULL);
xsetup = xcb_get_setup(conn);
// get the root window
screen_iterator = xcb_setup_roots_iterator(xsetup);
screen = screen_iterator.data;
root_win = screen->root;
// any function from xcb/randr.h fails with undefined reference.
resources = xcb_randr_get_screen_resources(conn, root_win);
}
Compile
# gcc tries
gcc -Wall main.cpp -o main `pkg-config --cflags --libs xcb`
g++ -Wall main.cpp -o main `pkg-config --cflags --libs xcb`
# clang tries
clang++ main.cpp -o main `pkg-config --cflags --libs xcb`
clang main.cpp -o main `pkg-config --cflags --libs xcb`
Result
gcc
/usr/bin/ld: /tmp/ccWR2GQL.o: in function `main':
main.cpp:(.text+0x6c): undefined reference to `xcb_randr_get_screen_resources'
collect2: error: ld returned 1 exit status
clang
/usr/bin/ld: /tmp/main-d114b5.o: in function `main':
main.cpp:(.text+0x67): undefined reference to `xcb_randr_get_screen_resources'
clang-7: error: linker command failed with exit code 1 (use -v to see invocation)
xcb libraries are split up in several different packages; so it goes that you need to pull in both xcb and xcb-randr libraries, explicitly:
... `pkg-config --cflags --libs xcb xcb-randr`
It's possible that your Linux distribution packages the randr library separately. Checking Fedora, it packages both xcb and xcb-rand in the libxcb-devel subpackage; but it's possible that your Linux distribution has a separate libxcb-randr-devel subpackage that you need to install.
Thank you very much n.m. and G.M. .
I was not linking the xcb-randr .
Solution:
clang++ main.cpp -o main `pkg-config --cflags --libs xcb` -lxcb-randr
Related
I've installed the libglfw3-dev:amd64 package on Ubuntu using the standard sudo apt get etc. My following compiling line is:
g++ -o output -IL/usr/lib/x86_64-linux-gnu -lglfw driver.o
My current c++ file is:
#include <GLFW/glfw3.h>
int main(void)
{
GLFWwindow* window;
if (!glfwInit())
return -1;
}
I've tried using local libraries of glfw and setting the -I and -L locations but nothing has seemed to work. I've made sure the .so and .h files are in their respective locations but I always get this error while running make:
g++ -o output -I/usr/include/GLFW -L/usr/lib/x86_64-linux-gnu -lglfw
driver.o
driver.o: In function `main':
driver.cpp:(.text+0x5): undefined reference to `glfwInit'
collect2: error: ld returned 1 exit status
Makefile:2: recipe for target 'output' failed
make: *** [output] Error 1
I've tried looking at all the other SO posts and they recommend compiling with tons of extra flags, but the only thing I've been able to draw from them is that something is wrong with my library since VScode detects the .h files. How can I compile this without any errors?
Have you tried swapping the linker arguments around? That is, compile with
g++ -o output driver.o -lglfw
The linker goes through the files from left to right, and it has to know which symbols from libraries you need, before the libraries are processed.
All is perfectly explained in the manual https://www.glfw.org/docs/latest/build_guide.html#build_link_pkgconfig
The key problem is in your -I/usr/include/GLFW and #include <GLFW/glfw3.h> that gives in sum the path /usr/include/GLFW/GLFW/glfw3.h. I suppose this is a wrong path to glfw3.h. compilation was successful because of the system default include path -I/usr/include.
Do not tune compiler flags manually, let pkg-config do
it for you.
A typical compile and link command-line when using the static version of the GLFW library may look like this:
g++ -o output `pkg-config --cflags glfw3` yourprog.c `pkg-config --static --libs glfw3`
If you are using the shared version of the GLFW library, simply omit the --static flag.
g++ -o output `pkg-config --cflags glfw3` yourprog.c `pkg-config --libs glfw3`
when i try to compile gstreamer basic tutorial 5 source, I get the following error:
/tmp/cczEt1RC.o: In function realize_cb':
basic-tutorial-5.c:(.text+0x50): undefined reference togst_x_overlay_get_type'
basic-tutorial-5.c:(.text+0x70): undefined reference to `gst_x_overlay_set_window_handle'
collect2: ld returned 1 exit status
Command I used to compile is:
gcc basic-tutorial-5.c pkg-config --cflags --libs gtk+-2.0 pkg-config --cflags --libs gstreamer-0.10 -o 5basic
How can I solve this error?
gstreamer sdk website had the gcc command but was hidden
gcc basic-tutorial-5.c -o basic-tutorial-5 pkg-config --cflags --libs gstreamer-interfaces-0.10 gtk+-2.0 gstreamer-0.10
I tried to compile my c++/opengl-project with the g++ command.
(I need this since I want to recompile it on every target system with a second self-written program.)
But when I execute:
g++ -Iinclude -Isrc $(pkg-config --cflags freetype2) -L/usr/X11R6/lib -L/usr/lib $(pkg-config --libs glew) -lglut $(pkg-config --libs glu) $(pkg-config --libs freetype2) main.cpp (some more source files) src/Vec4.cpp
I get lots of 'undefined references' for gl/glu/glut/glew-functions, so I guess something fails with the libs:
/tmp/ccUm2dEl.o: In function `Box::render()':
Box.cpp:(.text+0x6e8): undefined reference to `glEnable'
Box.cpp:(.text+0x72c): undefined reference to `glBindTexture'
Box.cpp:(.text+0x736): undefined reference to `glBegin'
...
TextureManager.cpp:(.text+0x23b): undefined reference to `glTexParameteri'
TextureManager.cpp:(.text+0x295): undefined reference to `glTexImage2D'
collect2: ld gab 1 als Ende-Status zurück
I did some research, but according to what I found out the above command should be correct.
I checked the pkg-config-calls as well and they seem to work.
Before I tried the g++ command I used the Codeblocks IDE to compile it and it worked. Here are my settings:
In Compiler settings|Other options:
`pkg-config --cflags freetype2`
In Linker settings|Link libraries:
glut
In Linker settings|Other linker options:
`pkg-config --libs glu`
`pkg-config --libs glew`
`pkg-config --libs freetype2`
In Search directories|Compiler:
include
src
My system (Ubuntu Precise):
$ uname -a
Linux andromeda 3.2.0-32-generic #51-Ubuntu SMP Wed Sep 26 21:33:09 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
$ g++ -dumpversion
4.6
glxinfo
GLX version: 1.4
OpenGL version string: 4.2.0 NVIDIA 304.43
Codeblocks-version: 10.04
Thanks in advice
The problem is most likely that you link in the wrong order. The GNU linker wants its libraries in kind of reverse order, so if you place the linker libraries last on the command line it should go better.
I am trying to compile my program on my new server, but it's not working for me at the moment.
Error log is:
rasmus#web01:~/c++$ make test
g++ `mysql_config --cflags --libs` main.cpp logger.cpp cpulogger.cpp -o test
/tmp/ccPaMZUy.o: In function `CPULogger':
/home/rasmus/c++/cpulogger.cpp:7: undefined reference to `mysql_init'
/home/rasmus/c++/cpulogger.cpp:8: undefined reference to `mysql_real_connect'
/home/rasmus/c++/cpulogger.cpp:10: undefined reference to `mysql_get_client_info'
/tmp/ccPaMZUy.o: In function `~CPULogger':
/home/rasmus/c++/cpulogger.cpp:16: undefined reference to `mysql_close'
collect2: ld returned 1 exit status
make: *** [all] Error 1
As you can see I am compiling against MySQL - I have checked that mysql.h is present in include paths.
What am I missing?
cpulogger.cpp has #include "cpulogger.h" at the top, then cpulogger.h has this:
#include <iostream>
#include <fstream>
#include <mysql/mysql.h>
The compiler does not complain about missing mysql/mysql.h, so that part must work?
Output of mysql_config:
rasmus#web01:~/c++$ mysql_config --cflags --libs
-I/usr/include/mysql -DBIG_JOINS=1 -fno-strict-aliasing -g
-L/usr/lib -lmysqlclient -lpthread -lz -lm -lrt -ldl
Makefile:
all:
g++ `mysql_config --cflags --libs` main.cpp logger.cpp cpulogger.cpp -o test
test: all
./test
It's a fresh Ubuntu server installation with a mysql-server install on it.
[solved]:
Putting linker libraries at the end of the compiler commands works.
all:
g++ main.cpp logger.cpp cpulogger.cpp -o test `mysql_config --cflags --libs`
See answer below for explanation.
The order of arguments to the linker is significant. Use mysql-config after listing the files that need it. The linker will see that cpulogger.o needs mysql_init and look in libraries listed after it for the symbol. If the libraries were listed earlier in the arguments they won't be searched again.
I've worked with opencv on linux in the past, but not with cuda. I've struggled with the following compilation error for months. And after trying many solutions i gave up and worked with windows. However, i really want to work on linux. This is the command i'm using to compile the threshold example given on the opencv_gpu website.
nvcc `pkg-config --libs opencv` -L. -L/usr/local/cuda/lib -lcuda -lcudart `pkg-config --cflags opencv` -I. -I/usr/local/cuda/include threshold.cpp -o threshold
here is the error:
/tmp/tmpxft_0000171b_00000000-1_threshold.o: In function `main':
threshold.cpp:(.text+0x124): undefined reference to `cv::gpu::Stream::Null()'
threshold.cpp:(.text+0x156): undefined reference to `cv::gpu::threshold(cv::gpu::GpuMat const&, cv::gpu::GpuMat&, double, double, int, cv::gpu::Stream&)'
threshold.cpp:(.text+0x16d): undefined reference to `cv::gpu::GpuMat::download(cv::Mat&) const'
/tmp/tmpxft_0000171b_00000000-1_threshold.o: In function `cv::gpu::GpuMat::GpuMat(cv::Mat const&)':
threshold.cpp:(.text._ZN2cv3gpu6GpuMatC1ERKNS_3MatE[cv::gpu::GpuMat::GpuMat(cv::Mat const&)]+0x63): undefined reference to `cv::gpu::GpuMat::upload(cv::Mat const&)'
/tmp/tmpxft_0000171b_00000000-1_threshold.o: In function `cv::gpu::GpuMat::~GpuMat()':
threshold.cpp:(.text._ZN2cv3gpu6GpuMatD1Ev[cv::gpu::GpuMat::~GpuMat()]+0xd): undefined reference to `cv::gpu::GpuMat::release()'
collect2: ld returned 1 exit status
make: *** [all] Error 1
In order to help you I had to download and install CUDA 4.0 (with driver 4.0.21) and then download and compiled OpenCV 2.3 for my Macbook Pro, on Mac OS X 10.6.8.
The sample code from OpenCV_GPU was successfully compiled on my machine through:
g++ threshold.cpp -o threshold `pkg-config --cflags --libs opencv` -lopencv_gpu
You were missing the flag -lopencv_gpu , which is not included by pkg-config.
This looks like a linker problem. I don't know, if nvcc follows the same conventions as gcc, but I would try:
nvcc `pkg-config --cflags opencv` -L. -L/usr/local/cuda/lib -I. -I/usr/local/cuda/include -o threshold threshold.cpp `pkg-config --libs opencv` -lcuda -lcudart
More in general: If you write
gcc t.cpp -lB -lA
it means that libB depends on symbols from libA; t.cpp can depend on symbols from libA and libB.
Instead of using pkg-config in the nvcc line I would suggest just manually pointing the compiler at the opencv library and include files. Perhaps you could just run pkg-config --libs opencv on the command line and copy the necessary libs into your nvcc command. It seems nvcc is only choking on the opencv libs (it can't find them for sure!).