Cuda compiling error when coming to g++ compiling step - cuda

nvcc -D_DEBUG --use_fast_math -I"/usr/local/cuda-9.0//include" -I"/usr/include/eigen3" -I"/home/xingfu/NVIDIA_CUDA-9.0_Samples/common/inc" -dlink --machine 64 -arch=sm_50 -c -o kernel_cuda.o ../CudaTest/kernel.cu
g++ -c -pipe -g -std=gnu++11 -Wall -W -D_REENTRANT -fPIC -DQT_DEPRECATED_WARNINGS -DQT_QML_DEBUG -DQT_CORE_LIB -I../CudaTest -I. -I/usr/local/cuda-9.0/include -isystem /usr/include/eigen3 -I../NVIDIA_CUDA-9.0_Samples/common/inc -isystem /usr/local/include -I../Qt5.11.0/5.11.0/gcc_64/include -I../Qt5.11.0/5.11.0/gcc_64/include/QtCore -I. -I../Qt5.11.0/5.11.0/gcc_64/mkspecs/linux-g++ -o LBDM.o ../CudaTest/LBDM.cpp
The two steps above have passed, however, when run the following step, the error occured:
g++ -Wl,-rpath,/home/xingfu/Qt5.11.0/5.11.0/gcc_64/lib -o CudaTest kernel_cuda.o LBDM.o -L/usr/local/cuda-9.0//lib64/ -lcuda -lcudart -lcublas -L/home/xingfu/CudaTest/../../../usr/local/lib/ -lopencv_core -lopencv_highgui -lopencv_imgproc -lopencv_imgcodecs -L/home/xingfu/Qt5.11.0/5.11.0/gcc_64/lib -lQt5Core -lpthread
The compiler error shows:
kernel_cuda.o: In function `__sti____cudaRegisterAll()':
tmpxft_00000e7d_00000000-5_kernel.cudafe1.cpp:(.text+0x177e): undefined reference to `__cudaRegisterLinkedBinary_41_tmpxft_00000e7d_00000000_6_kernel_cpp1_ii_channel'
How can I fix the error?
What's more,
I add the -dlink, because it shows the error when dealing the following step:
nvcc -D_DEBUG --use_fast_math -I"/usr/local/cuda-9.0//include" -I"/usr/include/eigen3" -I"/home/xingfu/NVIDIA_CUDA-9.0_Samples/common/inc" --machine 64 -arch=sm_50 -c -o kernel_cuda.o ../CudaTest/kernel.cu
and the error is:
ptxas fatal : Unresolved extern function 'cublasCreate_v2'
However, when I add -dlink, the error occured like I said above.
BTW, before I add -dlink, I can run a simple function in another test project like this:
__global__ void add(float* x, float * y, float* z, int n)
{
int index = threadIdx.x + blockIdx.x * blockDim.x;
int stride = blockDim.x * gridDim.x;
for (int i = index; i < n; i += stride)
{
z[i] = x[i] + y[i];
}
}
After I add -dlink, the test project shows an error:
cuda_code_cuda.o: In function `__sti____cudaRegisterAll()':
tmpxft_000017db_00000000-5_cuda_code.cudafe1.cpp:(.text+0x861): undefined reference to `__cudaRegisterLinkedBinary_44_tmpxft_000017db_00000000_6_cuda_code_cpp1_ii_5b538d80'
which is very similar to the above error.

For relocatable device code linking, which seems to be what you're after, the recommended sequence would be as follows. In addition, it appears your code is attempting to use the cublas device interface, so for good measure we'll add those libraries to the link steps:
#replace -dlink -c with -dc
nvcc -D_DEBUG --use_fast_math -I"/usr/local/cuda-9.0//include" -I"/usr/include/eigen3" -I"/home/xingfu/NVIDIA_CUDA-9.0_Samples/common/inc" -dc --machine 64 -arch=sm_50 -o kernel_cuda.o ../CudaTest/kernel.cu
#generate device-linked object with cublas device libraries
nvcc -D_DEBUG --use_fast_math -dlink --machine 64 -arch=sm_50 -o kernel_dlink.o kernel_cuda.o -lcublas -lcublas_device -lcudadevrt
#no change to this line
g++ -c -pipe -g -std=gnu++11 -Wall -W -D_REENTRANT -fPIC -DQT_DEPRECATED_WARNINGS -DQT_QML_DEBUG -DQT_CORE_LIB -I../CudaTest -I. -I/usr/local/cuda-9.0/include -isystem /usr/include/eigen3 -I../NVIDIA_CUDA-9.0_Samples/common/inc -isystem /usr/local/include -I../Qt5.11.0/5.11.0/gcc_64/include -I../Qt5.11.0/5.11.0/gcc_64/include/QtCore -I. -I../Qt5.11.0/5.11.0/gcc_64/mkspecs/linux-g++ -o LBDM.o ../CudaTest/LBDM.cpp
#add device-linked object to final link phase plus cublas device libraries
g++ -Wl,-rpath,/home/xingfu/Qt5.11.0/5.11.0/gcc_64/lib -o CudaTest kernel_cuda.o LBDM.o kernel_dlink.o -L/usr/local/cuda-9.0//lib64/ -lcuda -lcudart -lcublas -lcublas_device -lcudadevrt -L/home/xingfu/CudaTest/../../../usr/local/lib/ -lopencv_core -lopencv_highgui -lopencv_imgproc -lopencv_imgcodecs -L/home/xingfu/Qt5.11.0/5.11.0/gcc_64/lib -lQt5Core -lpthread

Related

PTX kernel name mangling

I cannot link my Cuda program when a kernel is compiled from ptx file.
main.cu:
extern
__global__ void kernel(int, float*);
int main()
{
...
kernel<<<...>>>(...);
...
}
kernel.cu
__global__
void kernel(int n, float* p)
{
...
}
If I compile like below, I have no problems and I get an executable:
nvcc -dc main.cu kernel.cu --gpu-architecture=sm_70
nvcc -dlink main.o kernel.o --gpu-architecture=sm_70 -o dlink.o
g++ dlink.o main.o kernel.o -lcudart
If I compile like below (by generating ptx), I get errors:
nvcc -ptx kernel.cu --gpu-architecture=sm_70
nvcc -dc main.cu kernel.ptx --gpu-architecture=sm_70
nvcc -dlink main.o kernel.o --gpu-architecture=sm_70 -o dlink.o
g++ dlink.o main.o kernel.o -lcudart
Error:
main.o: In function `main':
tmpxft_0000b5ce_00000000-5_main.cudafe1.cpp:(.text+0x4789): undefined reference to `kernel(int, float*)'
tmpxft_0000b5ce_00000000-5_main.cudafe1.cpp:(.text+0x497e): undefined reference to `kernel(int, float*)'
collect2: error: ld returned 1 exit status
I am following an example from CUDA_Compiler_Driver_NVCC.pdf.
What do I need to do to fix the error?
(This is CUDA 10.2).
If you want to write your own PTX (or modify PTX), the proper CUDA methodology to use is the CUDA driver API and associated compilation flow.
The CUDA vectorAddDrv sample code has all the plumbing and workflow that you need.

Can not link libmysqlclient.a?

I'm using Ubuntu 14.04, and I installed libmysqlclient-dev package already. But I always get link error because mysql_init symbol missing.
My source code, Makefile, run-time result and symbol info are as follows:
igsrd#naivechou/~/project/m01/uuid_sign>cat main.cpp
#include <cstdio>
#include <cstdlib>
#include "mysql/mysql.h"
int main(int argc,char** argv)
{
auto con = mysql_init(nullptr);
//printf("mysql client version : %s\n",mysql_get_client_info());
exit(EXIT_SUCCESS);
}
igsrd#naivechou/~/project/m01/uuid_sign>LANG= && make -B
g++ -o main.o -c main.cpp -std=c++11 -ggdb
g++ -o uuid_sign -L/usr/lib/x86_64-linux-gnu -lmysqlclient -lpthread -lz -lm -ldl main.o
main.o: In function `main':
/home/igsrd/project/m01/uuid_sign/main.cpp:6: undefined reference to `mysql_init'
collect2: error: ld returned 1 exit status
make: *** [uuid_sign] Error 1
igsrd#naivechou/~/project/m01/uuid_sign>nm -C /usr/lib/x86_64-linux-gnu/libmysqlclient.a | grep mysql_init
0000000000002b10 T mysql_init
0000000000002d30 T mysql_init_character_set
U mysql_init_character_set
Source is very simple, just one line to call mysql_init().
Making process shows every options for compiler and linker, I think there are no missing options.
Error message is undefined reference of linking error, so I dump libmysqlclient.a to grep the mysql_init, and it is not on undefined state.
Now I really have no idea. What's wrong with this ?
Change your second command, try this (change the position of main.o):
g++ -o uuid_sign main.o -L/usr/lib/x86_64-linux-gnu -lmysqlclient -lpthread -lz -lm -ldl

Does nvcc support "-pthread" option internally?

I try to use nvcc to build following multi-thread program which is built by "gcc -pthread a.c" before:
$ cat a.c
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
void *myThreadFun(void *vargp)
{
printf("myThreadFun \n");
return NULL;
}
int main()
{
pthread_t tid;
printf("Before Thread\n");
pthread_create(&tid, NULL, myThreadFun, NULL);
pthread_join(tid, NULL);
printf("After Thread\n");
exit(0);
}
Execute "nvcc -pthread a.c":
$ nvcc -pthread a.c
nvcc fatal : Unknown option 'pthread'
This topic said nvcc supports building multi-thread program without using -pthread option. And my test also seems right:
$ nvcc a.c
nvcc warning : The 'compute_20', 'sm_20', and 'sm_21' architectures are deprecated, and may be removed in a future release (Use -Wno-deprecated-gpu-targets to suppress warning).
$ ldd a.out
linux-vdso.so.1 (0x00007ffcff79e000)
librt.so.1 => /usr/lib/librt.so.1 (0x00007fd4f5a43000)
libpthread.so.0 => /usr/lib/libpthread.so.0 (0x00007fd4f5825000)
libdl.so.2 => /usr/lib/libdl.so.2 (0x00007fd4f5621000)
libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00007fd4f5299000)
libm.so.6 => /usr/lib/libm.so.6 (0x00007fd4f4f86000)
libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x00007fd4f4d6f000)
libc.so.6 => /usr/lib/libc.so.6 (0x00007fd4f49cb000)
/lib64/ld-linux-x86-64.so.2 (0x00007fd4f5c4b000)
But I can't find the proof from nvcc official document. Could anyone help to affirm it?
No nvcc doesn't support a pthread option. In fact, it knows nothing about pthreads. The pthread dependency is coming from dependencies in the CUDA runtime libraries. It has nothing to do with what is in your code. nvcc doesn't even compile that code, it is passed to your host compiler. nvcc is a compiler driver. It just steers compilation using other compilers. In this case the host C++ compiler.
You can see what actually happens like this:
$ nvcc -arch=sm_52 -v pthread_confusion.c
#$ _SPACE_=
#$ _CUDART_=cudart
#$ _HERE_=/opt/cuda-8.0/bin
#$ _THERE_=/opt/cuda-8.0/bin
#$ _TARGET_SIZE_=
#$ _TARGET_DIR_=
#$ _TARGET_SIZE_=64
#$ TOP=/opt/cuda-8.0/bin/..
#$ NVVMIR_LIBRARY_DIR=/opt/cuda-8.0/bin/../nvvm/libdevice
#$ LD_LIBRARY_PATH=/opt/cuda-8.0/bin/../lib:/opt/cuda-8.0/lib64:/usr/lib/nx/X11/Xinerama:/usr/lib/nx/X11
#$ PATH=/opt/cuda-8.0/bin/../open64/bin:/opt/cuda-8.0/bin/../nvvm/bin:/opt/cuda-8.0/bin:/usr/local/bin:/usr/bin:/bin:/opt/cuda-8.0/bin
#$ INCLUDES="-I/opt/cuda-8.0/bin/..//include"
#$ LIBRARIES= "-L/opt/cuda-8.0/bin/..//lib64/stubs" "-L/opt/cuda-8.0/bin/..//lib64"
#$ CUDAFE_FLAGS=
#$ PTXAS_FLAGS=
#$ gcc -c -x c -D__NVCC__ "-I/opt/cuda-8.0/bin/..//include" -D"__CUDACC_VER__=80044" -D"__CUDACC_VER_BUILD__=44" -D"__CUDACC_VER_MINOR__=0" -D"__CUDACC_VER_MAJOR__=8" -m64 -o "/tmp/tmpxft_000069ca_00000000-4_pthread_confusion.o" "pthread_confusion.c"
#$ nvlink --arch=sm_52 --register-link-binaries="/tmp/tmpxft_000069ca_00000000-2_a_dlink.reg.c" -m64 "-L/opt/cuda-8.0/bin/..//lib64/stubs" "-L/opt/cuda-8.0/bin/..//lib64" -cpu-arch=X86_64 "/tmp/tmpxft_000069ca_00000000-4_pthread_confusion.o" -lcudadevrt -o "/tmp/tmpxft_000069ca_00000000-5_a_dlink.sm_52.cubin"
#$ fatbinary --create="/tmp/tmpxft_000069ca_00000000-3_a_dlink.fatbin" -64 -link "--image=profile=sm_52,file=/tmp/tmpxft_000069ca_00000000-5_a_dlink.sm_52.cubin" --embedded-fatbin="/tmp/tmpxft_000069ca_00000000-3_a_dlink.fatbin.c"
#$ rm /tmp/tmpxft_000069ca_00000000-3_a_dlink.fatbin
#$ gcc -c -x c++ -DFATBINFILE="\"/tmp/tmpxft_000069ca_00000000-3_a_dlink.fatbin.c\"" -DREGISTERLINKBINARYFILE="\"/tmp/tmpxft_000069ca_00000000-2_a_dlink.reg.c\"" -I. "-I/opt/cuda-8.0/bin/..//include" -D"__CUDACC_VER__=80044" -D"__CUDACC_VER_BUILD__=44" -D"__CUDACC_VER_MINOR__=0" -D"__CUDACC_VER_MAJOR__=8" -m64 -o "/tmp/tmpxft_000069ca_00000000-6_a_dlink.o" "/opt/cuda-8.0/bin/crt/link.stub"
#$ g++ -m64 -o "a.out" -Wl,--start-group "/tmp/tmpxft_000069ca_00000000-6_a_dlink.o" "/tmp/tmpxft_000069ca_00000000-4_pthread_confusion.o" "-L/opt/cuda-8.0/bin/..//lib64/stubs" "-L/opt/cuda-8.0/bin/..//lib64" -lcudadevrt -lcudart_static -lrt -lpthread -ldl -Wl,--end-group
Here, the boilerplate linking phase includes both the CUDA runtime library and the pthreads library.
If you want to be explicit with the host compiler, pass -Xcompiler="-pthread"

Why do I get a segmentation fault when calling a CUDA kernel directly from a shared library?

The way I tried it (see question title) it compiled, but I get a segmentation fault. So is it me, CMake or CUDA which doesn't support direct kernel calls from a shared library? The solution doesn't have to be with CMake
Further details:
I have the following file structure:
testKernel.hpp
__global__ void kernelTest( float x );
void callKernel( float x );
testKernel.cu
#include "testKernel.hpp"
__global__ void kernelTest( float x ) {}
void callKernel( float x ) { kernelTest<<<1,1>>>( x ); }
useKernel.cu
#include <cstdio>
#include "testKernel.hpp"
int main( void )
{
kernelTest<<<1,1>>>( 3.0f );
//callKernel( 3.0f );
printf("OK\n");
return 0;
}
CMakeLists.txt
cmake_minimum_required(VERSION 3.3.1)
project(testKernelCall)
find_package(CUDA REQUIRED)
cuda_add_library( ${PROJECT_NAME} SHARED testKernel.cu testKernel.hpp )
target_link_libraries( ${PROJECT_NAME} ${CUDA_LIBRARIES} )
cuda_add_executable("useKernel" useKernel.cu)
target_link_libraries("useKernel" ${PROJECT_NAME})
Compiling and running this with:
cmake .; make && ./useKernel
results in a segmentation fault. The backtrace with gdb is:
Program received signal SIGSEGV, Segmentation fault.
0x00007ffff75726bd in cudart::configData::addArgument(void const*, unsigned long, unsigned long) ()
from ./libtestKernelCall.so
(gdb) bt
#0 0x00007ffff75726bd in cudart::configData::addArgument(void const*, unsigned long, unsigned long) ()
from ./libtestKernelCall.so
#1 0x00007ffff7562eb7 in cudart::cudaApiSetupArgument(void const*, unsigned long, unsigned long) ()
from ./libtestKernelCall.so
#2 0x00007ffff7591ca2 in cudaSetupArgument ()
from ./libtestKernelCall.so
#3 0x00007ffff7556125 in __device_stub__Z10kernelTestf (__par0=3)
at /tmp/tmpxft_00003900_00000000-4_testKernel.cudafe1.stub.c:7
#4 0x00007ffff755616c in kernelTest (__cuda_0=3) at ./testKernel.cu:2
#5 0x000000000040280e in main () at ./useKernel.cu:6
Tested with (which means the segfault appears in those setups):
Setup 1
cmake 3.4.1
CUDA 7.0.27
g++ 4.9.2
Debian
Setup 2
cmake 3.3.1
CUDA 6.5.14
g++ 4.7.1
There are two ways to solve this error:
change SHARED to STATIC in CMakeList.txt
use the wrapper function callKernel instead of calling the kernel directly
I don't really know how to build a CUDA shared library without CMake. I know how to build a CUDA static library, but that case seems to work with CMake, so I didn't test it without CMake.
Here are the relevant CMake commands I got with make VERBOSE=1. I changed absolute paths to relative paths, where possible, but I wasn't sure about all these library paths. Putting these commands in a file and sourcing that file compiles the shared library and the program correctly and "correctly" leads to the segmentation fault. I also added command because for me nvcc is aliased with the `-ccbin`` option.
make.sh
command nvcc "./testKernel.cu" -c -o "./testKernel.cu.o" -ccbin /usr/bin/cc -m64 -DtestKernelCall_EXPORTS -Xcompiler ,\"-fPIC\",\"-g\" -DNVCC -I/opt/cuda-7.0/include -I/opt/cuda-7.0/include
/usr/bin/c++ -fPIC -shared -Wl,-soname,libtestKernelCall.so -o libtestKernelCall.so ./testKernel.cu.o /opt/cuda-7.0/lib64/libcudart_static.a -lpthread /usr/lib/x86_64-linux-gnu/librt.so /usr/lib/x86_64-linux-gnu/libdl.so /opt/cuda-7.0/lib64/libcudart_static.a -lpthread /usr/lib/x86_64-linux-gnu/librt.so /usr/lib/x86_64-linux-gnu/libdl.so
command nvcc "./useKernel.cu" -c -o "./useKernel.cu.o" -ccbin /usr/bin/cc -m64 -Xcompiler ,\"-g\" -DNVCC -I/opt/cuda-7.0/include -I/opt/cuda-7.0/include
/usr/bin/c++ ./useKernel.cu.o -o useKernel -rdynamic /opt/cuda-7.0/lib64/libcudart_static.a -lpthread /usr/lib/x86_64-linux-gnu/librt.so /usr/lib/x86_64-linux-gnu/libdl.so libtestKernelCall.so /opt/cuda-7.0/lib64/libcudart_static.a -lpthread /usr/lib/x86_64-linux-gnu/librt.so /usr/lib/x86_64-linux-gnu/libdl.so -Wl,-rpath,"."
Your code compiles and runs correctly for me using ordinary nvcc commands (not CMake) if I add the -cudart shared switch to each nvcc command. Here's a fully-worked sequence:
$ cat testKernel.hpp
__global__ void kernelTest( float x );
void callKernel( float x );
$ cat testKernel.cu
#include "testKernel.hpp"
__global__ void kernelTest( float x ) {}
void callKernel( float x ) { kernelTest<<<1,1>>>( x ); }
$ cat useKernel.cu
#include <cstdio>
#include "testKernel.hpp"
int main( void )
{
kernelTest<<<1,1>>>( 3.0f );
//callKernel( 3.0f );
cudaDeviceSynchronize();
printf("OK\n");
return 0;
}
$ nvcc -shared -cudart shared -o test.so -Xcompiler -fPIC testKernel.cu
$ nvcc -cudart shared -o test test.so useKernel.cu
$ cuda-memcheck ./test
========= CUDA-MEMCHECK
OK
========= ERROR SUMMARY: 0 errors
$
If I omit -cudart shared on either of the above nvcc commands, then the compile will still proceed, but on execution I will witness the aforementioned seg fault. Tested with CUDA 7.5 on Fedora 20.
Regarding your CMake setup, it's necessary to link against the shared cudart, according to my testing. Therefore it's insufficient to add -cudart shared to the -c commands (which are compile commands. Sorry if I was unclear. My "compile" commands above are doing both compiling and linking, at each step.)
When linking with nvcc, the correct switch is -cudart shared. However, your make.sh indicates final link is being done by the host c++ compiler:
command nvcc "./testKernel.cu" -c -o "./testKernel.cu.o" -ccbin /usr/bin/cc -m64 -DtestKernelCall_EXPORTS -Xcompiler ,\"-fPIC\",\"-g\" -DNVCC -I/opt/cuda-7.0/include -I/opt/cuda-7.0/include
/usr/bin/c++ -fPIC -shared -Wl,-soname,libtestKernelCall.so -o libtestKernelCall.so ./testKernel.cu.o /opt/cuda-7.0/lib64/libcudart_static.a -lpthread /usr/lib/x86_64-linux-gnu/librt.so /usr/lib/x86_64-linux-gnu/libdl.so /opt/cuda-7.0/lib64/libcudart_static.a -lpthread /usr/lib/x86_64-linux-gnu/librt.so /usr/lib/x86_64-linux-gnu/libdl.so
command nvcc "./useKernel.cu" -c -o "./useKernel.cu.o" -ccbin /usr/bin/cc -m64 -Xcompiler ,\"-g\" -DNVCC -I/opt/cuda-7.0/include -I/opt/cuda-7.0/include
/usr/bin/c++ ./useKernel.cu.o -o useKernel -rdynamic /opt/cuda-7.0/lib64/libcudart_static.a -lpthread /usr/lib/x86_64-linux-gnu/librt.so /usr/lib/x86_64-linux-gnu/libdl.so libtestKernelCall.so /opt/cuda-7.0/lib64/libcudart_static.a -lpthread /usr/lib/x86_64-linux-gnu/librt.so /usr/lib/x86_64-linux-gnu/libdl.so -Wl,-rpath,"."
In that case, you don't want to link against:
/opt/cuda-7.0/lib64/libcudart_static.a
but instead against libcudart.so:
/opt/cuda-7.0/lib64/libcudart.so
If you were editing your make.sh directly, you would want to make that change in both of the /usr/bin/c++ command lines you have shown. For example, if I were to modify my compile sequence already presented to reflect your usage of the host c++ compiler to do the linking, it would look like this:
$ nvcc -c -Xcompiler -fPIC testKernel.cu
$ g++ -fPIC -shared -o test.so -L/usr/local/cuda/lib64 -lcudart testKernel.o
$ nvcc -c useKernel.cu
$ g++ -o test -L/usr/local/cuda/lib64 -lcudart test.so useKernel.o
$ cuda-memcheck ./test
========= CUDA-MEMCHECK
OK
========= ERROR SUMMARY: 0 errors
$
put set(CUDA_USE_STATIC_CUDA_RUNTIME OFF) before find_package(CUDA REQUIRED) will do the job equivalent to set(CUDA_LIBRARIES "${CUDA_TOOLKIT_ROOT_DIR}/lib64/libcudart.so")
This is an extension to Robert Crovella's answer.
I use the following CMakeLists.txt and it works well.
cmake_minimum_required(VERSION 3.8)
project(cmake_and_cuda LANGUAGES CXX CUDA)
add_library(my_cu SHARED testKernel.cu testKernel.h)
target_link_libraries(my_cu PRIVATE cudart) #MUST!!
set(CMAKE_CUDA_FLAGS "-shared -cudart shared -Xcompiler -fPIC"
CACHE STRING "Use libcudart.dylib" FORCE)
set(CMAKE_MACOSX_RPATH FALSE)
add_executable(app useKernel.cu)
target_link_libraries(app PRIVATE cudart) #MUST!!
target_link_libraries(app PRIVATE my_cu)
I'm using CMake 3.10 and my OS is OS X EI Capitan 10.11.6.
For me, if I don't set CMAKE_MACOSX_RPATH to FALSE, I will get a Library not loaded error. Maybe it is not necessary for you.
Note that since CMake 3.8, the FindCUDA is superseded, so setting CUDA_USE_STATIC_CUDA_RUNTIME affects nothing.
You can check this post and this document for details.
In addition, this post provides a good example about how to deal with CUDA after CMake 3.8.

Ruby - Gem - mysql - Failed to build gem native extension

since two days I'm facing a problem I can't solve. I'm trying to install redmine on a debian machine. When it comes to installation for the gem mysql it fails. I don't know what to do anymore. My last instance is your help.
Error
root#host:~# gem1.8 install mysql
Building native extensions. This could take a while...
ERROR: Error installing mysql:
ERROR: Failed to build gem native extension.
/usr/bin/ruby1.8 extconf.rb
checking for mysql_ssl_set()... no
checking for rb_str_set_len()... no
checking for rb_thread_start_timer()... no
checking for mysql.h... no
checking for mysql/mysql.h... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.
Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/usr/bin/ruby1.8
--with-mysql-config
--without-mysql-config
Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/mysql-2.8.1 for inspection.
Results logged to /usr/lib/ruby/gems/1.8/gems/mysql-2.8.1/ext/mysql_api/gem_make.out
What I've tried
Installing packages by instruction: http://wiki.rubyonrails.org/database-support/mysql#linux_ubuntu
installing with mysql_config parameter
root#host:~# find / -name mysql_config
/usr/bin/mysql_config
root#host:~# gem1.8 install mysql -- --with-mysql-config=/usr/bin/mysql_config
System
user#host:~# uname -a
Linux www.example.org 2.6.18-028stab070.4 #1 SMP Tue Aug 17 18:32:47 MSD 2010 x86_64 GNU/Linux
root#s15428277:~# aptitude search '~i (mysql|ruby)|mysql.*dev'
i A libdbd-mysql-perl - A Perl5 database interface to the MySQL database
p libghc6-hsql-mysql-dev - Multi-Database Interface System for Haskell
p libgnademysql-dev - GNat Ada Database Environment - MySQL programming interface
p liblua5.1-sql-mysql-dev - luasql development files for the lua language version 5.1
i libmysql++-dev - mysql C++ library bindings (development)
i A libmysql++2c2a - mysql C++ library bindings (runtime)
p libmysql-ocaml-dev - OCaml bindings for MySql
v libmysqlclient-dev -
i libmysqlclient15-dev - MySQL database development files
i A libmysqlclient15off - MySQL database client library
i libopenssl-ruby1.8 - OpenSSL interface for Ruby 1.8
i A libreadline-ruby1.8 - Readline interface for Ruby 1.8
i A libruby1.8 - Libraries necessary to run Ruby 1.8
i libsqlite3-ruby1.8 - SQLite3 interface for Ruby 1.8
i A mysql-client-5.0 - MySQL database client binaries
i A mysql-common - MySQL database common files
i mysql-server - MySQL database server (metapackage depending on the latest version)
i A mysql-server-5.0 - MySQL database server binaries
i ruby1.8 - Interpreter of object-oriented scripting language Ruby 1.8
i ruby1.8-dev - Header files for compiling extension modules for the Ruby 1.8
root#host:~# gem1.8 --version
1.3.7
root#host:~# ruby1.8 --version
ruby 1.8.7 (2008-08-11 patchlevel 72) [x86_64-linux]
Files
mkmf.log
have_func: checking for mysql_ssl_set()... -------------------- no
"cc -o conftest -I. -I/usr/lib/ruby/1.8/x86_64-linux -I/usr/lib/ruby/gems/1.8/gems/mysql-2.8.1/ext/mysql_api -I/usr/include/mysql -DBIG_JOINS=1 -fPIC -fno-strict-aliasing -g -g -O2 -fPIC conftest.c -L. -L/usr/lib -L. -rdynamic -Wl,-export-dynamic -L/usr/lib/mysql -lmysqlclient -lruby1.8-static -L/usr/lib/mysql -lmysqlclient -lpthread -ldl -lcrypt -lm -lc"
checked program was:
/* begin */
1: /*top*/
2: int main() { return 0; }
3: int t() { void ((*volatile p)()); p = (void ((*)()))mysql_ssl_set; return 0; }
/* end */
"cc -o conftest -I. -I/usr/lib/ruby/1.8/x86_64-linux -I/usr/lib/ruby/gems/1.8/gems/mysql-2.8.1/ext/mysql_api -I/usr/include/mysql -DBIG_JOINS=1 -fPIC -fno-strict-aliasing -g -g -O2 -fPIC conftest.c -L. -L/usr/lib -L. -rdynamic -Wl,-export-dynamic -L/usr/lib/mysql -lmysqlclient -lruby1.8-static -L/usr/lib/mysql -lmysqlclient -lpthread -ldl -lcrypt -lm -lc"
checked program was:
/* begin */
1: /*top*/
2: int main() { return 0; }
3: int t() { mysql_ssl_set(); return 0; }
/* end */
--------------------
have_func: checking for rb_str_set_len()... -------------------- no
"cc -o conftest -I. -I/usr/lib/ruby/1.8/x86_64-linux -I/usr/lib/ruby/gems/1.8/gems/mysql-2.8.1/ext/mysql_api -I/usr/include/mysql -DBIG_JOINS=1 -fPIC -fno-strict-aliasing -g -g -O2 -fPIC conftest.c -L. -L/usr/lib -L. -rdynamic -Wl,-export-dynamic -L/usr/lib/mysql -lmysqlclient -lruby1.8-static -L/usr/lib/mysql -lmysqlclient -lpthread -ldl -lcrypt -lm -lc"
checked program was:
/* begin */
1: /*top*/
2: int main() { return 0; }
3: int t() { void ((*volatile p)()); p = (void ((*)()))rb_str_set_len; return 0; }
/* end */
"cc -o conftest -I. -I/usr/lib/ruby/1.8/x86_64-linux -I/usr/lib/ruby/gems/1.8/gems/mysql-2.8.1/ext/mysql_api -I/usr/include/mysql -DBIG_JOINS=1 -fPIC -fno-strict-aliasing -g -g -O2 -fPIC conftest.c -L. -L/usr/lib -L. -rdynamic -Wl,-export-dynamic -L/usr/lib/mysql -lmysqlclient -lruby1.8-static -L/usr/lib/mysql -lmysqlclient -lpthread -ldl -lcrypt -lm -lc"
checked program was:
/* begin */
1: /*top*/
2: int main() { return 0; }
3: int t() { rb_str_set_len(); return 0; }
/* end */
--------------------
have_func: checking for rb_thread_start_timer()... -------------------- no
"cc -o conftest -I. -I/usr/lib/ruby/1.8/x86_64-linux -I/usr/lib/ruby/gems/1.8/gems/mysql-2.8.1/ext/mysql_api -I/usr/include/mysql -DBIG_JOINS=1 -fPIC -fno-strict-aliasing -g -g -O2 -fPIC conftest.c -L. -L/usr/lib -L. -rdynamic -Wl,-export-dynamic -L/usr/lib/mysql -lmysqlclient -lruby1.8-static -L/usr/lib/mysql -lmysqlclient -lpthread -ldl -lcrypt -lm -lc"
checked program was:
/* begin */
1: /*top*/
2: int main() { return 0; }
3: int t() { void ((*volatile p)()); p = (void ((*)()))rb_thread_start_timer; return 0; }
/* end */
"cc -o conftest -I. -I/usr/lib/ruby/1.8/x86_64-linux -I/usr/lib/ruby/gems/1.8/gems/mysql-2.8.1/ext/mysql_api -I/usr/include/mysql -DBIG_JOINS=1 -fPIC -fno-strict-aliasing -g -g -O2 -fPIC conftest.c -L. -L/usr/lib -L. -rdynamic -Wl,-export-dynamic -L/usr/lib/mysql -lmysqlclient -lruby1.8-static -L/usr/lib/mysql -lmysqlclient -lpthread -ldl -lcrypt -lm -lc"
checked program was:
/* begin */
1: /*top*/
2: int main() { return 0; }
3: int t() { rb_thread_start_timer(); return 0; }
/* end */
--------------------
have_header: checking for mysql.h... -------------------- no
"cc -E -I. -I/usr/lib/ruby/1.8/x86_64-linux -I/usr/lib/ruby/gems/1.8/gems/mysql-2.8.1/ext/mysql_api -I/usr/include/mysql -DBIG_JOINS=1 -fPIC -fno-strict-aliasing -g -g -O2 -fPIC conftest.c -o conftest.i"
checked program was:
/* begin */
1: #include
/* end */
--------------------
have_header: checking for mysql/mysql.h... -------------------- no
"cc -E -I. -I/usr/lib/ruby/1.8/x86_64-linux -I/usr/lib/ruby/gems/1.8/gems/mysql-2.8.1/ext/mysql_api -I/usr/include/mysql -DBIG_JOINS=1 -fPIC -fno-strict-aliasing -g -g -O2 -fPIC conftest.c -o conftest.i"
checked program was:
/* begin */
1: #include
/* end */
--------------------
It looks like you are on the right track. Even though you appear to have the mysql libraries installed, you need to ensure that the MySQL development header files and their dependencies are fully installed in order for the MySQL gem to be compiled.
Try:
sudo apt-get install mysql-dev
And then:
sudo gem install mysql --
--with-mysql-config=/usr/local/mysql/bin/mysql_config
Clearly, the exact command depends upon where the mysql-dev files are installed.
I had the same problem.
The solution for me was to install ruby-dev.
Maybe it helps somebody else, I see you've already solved your porblem.