I'm having some trouble compiling a OpenCL aplication. When I run:
gcc -L/usr/include/CL -lOpenCL opencl-app.c -o out -lm
I receive the message:
/usr/bin/ld: cannot find -lOpenCL
The library exists, cause, when I run:
sudo find / -iname "*opencl*"
I receive :
/var/cache/apt/archives/opencl-headers_1.2-2013.10.23-1_all.deb
/var/lib/dpkg/info/opencl-headers.md5sums
/var/lib/dpkg/info/opencl-headers.list
/usr/include/CL/opencl.h
/usr/share/lintian/overrides/opencl-headers
/usr/share/doc/opencl-headers
/home/opuser/OpenCL
I'm including in the code this way:
#ifdef APPLE
#include <OpenCL/opencl.h>
#else
#include <CL/opencl.h>
#endif
I'm Using ubuntu 14.04. What can I do? Thanks!
Related
I am trying to compile the mosquitto library with my custom c program. So WHat I have done is wrote a hello.c file, git cloned the latest mosquitto library from the below repository:
https://github.com/eclipse/mosquitto.git
and compiled it with the make command as below:
make
I had to remove the doc target as it was asking for some dependancy library. I don't have admin rights on this machine, hence don't want to be blocked by any dependancy lib. After the compilation what I have is the below:
src/mosquitto
./lib/libmosquitto.so.1
The I copied the libmosquitto.so.1 shared lib into a local folder called ~/hello/:
~/hello$ cp ~/mosquitto/lib/libmosquitto.so.1 .
then wrote a hello.c inside ~/hello/ which is as below:
#include <stdio.h>
int main()
{
printf("Hello World\n");
return 0;
}
I can compile the hello.c and run it as below:
gcc -o hello hello.c
./hello
Hello World
But if I try to link the binary with the mosquitto library I get an error like the below:
gcc -o hello hello.c -lmosquitto
/usr/bin/ld: cannot find -lmosquitto
collect2: error: ld returned 1 exit status
The libmosquitto.so.1 lives in the same folder as the hello.c. I don't want to install the mosquitto library, rather would like to keep in a local folder and be able to link it. I have also tried the below with the hope that the -L. would point the linker to the present directory for the shared lib file but still get the same error:
gcc -o hello hello.c -L. -lmosquitto
/usr/bin/ld: cannot find -lmosquitto
collect2: error: ld returned 1 exit status
My ultimate objective is to cross compile the library for an arm target. So really need to understand how the linking of the shared library is failing so that I can use the same experience while cross compiling and link for the target. At the moment I am doing this on a x86 platform.
Can anyone please help?
/usr/bin/ld: cannot find -lmosquitto
The linker doesn't look for libmosquitto.so.1 -- it only looks for libmosquitto.a or libmosquitto.so.
Solution: ln -s libmosquitto.so.1 libmosquitto.so
./pub: error while loading shared libraries: libmosquitto.so.1: cannot open shared object file: No such file or directory
The problem here is that the runtime loader doesn't look in the current directory for libmosquitto.so.1 -- it only looks in system-configured directories.
You could fix this by adding export LD_LIBRARY_PATH=$HOME/mosquitto/lib, but this is suboptimal -- your binary will work or not depending on the environment.
A better solution is to change your link command like so:
gcc -o hello hello.c -L. -lmosquitto -Wl,-rpath=$HOME/mosquitto/lib
I have run gcc cross compiler from ubuntu(x86) to arm. this cross compiler works fine on ubuntu 14, and not I try in on ubuntu 18.
I tried to compile simple program
#include <stdio.h>
void main() {
printf("h\n");
}
gcc test.c -o test
When I compile it with gcc (to x86) all works fine, but when I compile it with cross compiler arm gcc I got error ...arm-buildroot-linux-uclibcgnueabu/4.*.*/cc1 : error while loading shared libraries: libmpfr.so.4 cannot open shared object file: No such file or directory
When I serach I can findlibmpfr.so.4 in the cross compiler path under /usr/lib
So even arm-gcc test.c -o test -L "<path_to_compiler>/usr/lib" got same error . and even export LD_LIBRARY_PATH=<path_to_compiler>/usr/lib didn't help
I wrote the simple program in linux ubuntu, when I use g++ there is no error but when I use gcc I see this error:
test.c:1:17: fatal error: cmath: No such file or directory #include <cmath>
Note : "as a matter of fact I see this error in compiling the package, I thought it might be related to gcc library which is not set to linux environment, so I wrote the simple program to determine the error clearly and whitout dependency!"
so the program should compile with gcc so that I can over come the main problem.
I khow that I can use math.h instead of cmath, but the packege used the cmath!
this is the simple program:
/*test.c*/
#include <cmath>
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
using namespace std;
int main(){
double sinx = sin(3.14/3);
cout<< "sinx= " << sinx;
return 0;
}
here is cmath pathes:
root#geant4:/# find -name cmath
./opt/root5.32.00/cint/cint/include/cmath
./app/gcc/4.8.0/include/c++/4.8.0/ext/cmath
./app/gcc/4.8.0/include/c++/4.8.0/cmath
./app/gcc/4.8.0/include/c++/4.8.0/tr1/cmath
./usr/include/boost/compatibility/cpp_c_headers/cmath
./usr/include/boost/tr1/tr1/cmath
./usr/include/c++/4.5/cmath
./usr/include/c++/4.5/tr1_impl/cmath
./usr/include/c++/4.5/tr1/cmath
./usr/include/c++/4.6/cmath
./usr/include/c++/4.6/tr1/cmath
./usr/share/gccxml-0.9/GCC/2.95/cmath
./gcc-build/gcc-4.8.0/stage1-i686-pc-linux-gnu/libstdc++-v3/include/ext/cmath
./gcc-build/gcc-4.8.0/stage1-i686-pc-linux-gnu/libstdc++-v3/include/cmath
./gcc-build/gcc-4.8.0/stage1-i686-pc-linux-gnu/libstdc++-v3/include/tr1/cmath
./gcc-build/gcc-4.8.0/i686-pc-linux-gnu/libstdc++-v3/include/ext/cmath
./gcc-build/gcc-4.8.0/i686-pc-linux-gnu/libstdc++-v3/include/cmath
./gcc-build/gcc-4.8.0/i686-pc-linux-gnu/libstdc++-v3/include/tr1/cmath
./gcc-build/gcc-4.8.0/libstdc++-v3/include/ext/cmath
./gcc-build/gcc-4.8.0/libstdc++-v3/include/c/cmath
./gcc-build/gcc-4.8.0/libstdc++-v3/include/c_global/cmath
./gcc-build/gcc-4.8.0/libstdc++-v3/include/c_std/cmath
./gcc-build/gcc-4.8.0/libstdc++-v3/include/tr1/cmath
./gcc-build/gcc-4.8.0/libstdc++-v3/testsuite/26_numerics/headers/cmath
./gcc-build/gcc-4.8.0/libstdc++-v3/testsuite/tr1/8_c_compatibility/cmath
./gcc-build/gcc-4.8.0/prev-i686-pc-linux-gnu/libstdc++-v3/include/ext/cmath
./gcc-build/gcc-4.8.0/prev-i686-pc-linux-gnu/libstdc++-v3/include/cmath
./gcc-build/gcc-4.8.0/prev-i686-pc-linux-gnu/libstdc++-v3/include/tr1/cmath
and after installing gcc-4.8 I did this instruction:
root#geant4:~/Desktop# update-alternatives --install /usr/bin/gcc gcc /app/gcc/4.8.0/bin/gcc 40 --slave /usr/bin/g++ g++ /app/gcc/4.8.0/bin/g++
root#geant4:~/Desktop#update-alternatives --install /usr/bin/gcc gcc /app/gcc/4.8.0/bin/gcc 60 --slave /usr/bin/g++ g++ /app/gcc/4.8.0/bin/g++
root#geant4:~/Desktop# update-alternatives --config gcc
to make gcc-4.8 my default gcc.
now
root#geant4:~/Desktop# gcc --version
gcc (GCC) 4.8.0
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
as a matter of fact I wrote the main problem in https://askubuntu.com/questions/309195/cmath-no-such-file-or-directory-include-cmath
please help me
I don`t know what to do.
thanks
Some basics::
GCC:: GNU Compiler Collection
G++:: GNU C++ Compiler
Both are drivers which calls the compilers as needed.
Clearing your doubt::
The problem with GCC is that it doesn't links in the std C++ libraries by default as G++ does. GCC is just a front-end. The actual compiler is cc1plus. So it is always advisable to use G++ when compiling C++ files. The result can be same with both GCC and G++ if you do know the exact arguments to link them. You may find this link helpful.
But if you still want to use GCC, use it with linker-option -lstdc++ at the end of the command. This linker-option is added by default when you use G++. You can verify this by compiling your code using GCC with -### option and it will show you that -lstdc++ option is missing.
Compile C++ source files with g++, not gcc.
First I install sctp on Ubuntu 12.04
sudo apt-get install libsctp-dev lksctp-tools
Then in my .c file,I include :
#include < netinet/in.h >
#include < netinet/sctp.h >
#include < sys/socket.h >
#include < stdlib.h >
#include < unistd.h >
howerver,when I compiled with gcc,the result is:
undefined reference to `sctp_recvmsg'
undefined reference to `sctp_get_no_strms'
undefined reference to `sctp_sendmsg'
What is wrong?
If you really compile with gcc temp.c -o temp then you are not linking any libraries (except the default libc.6.so), and you need some additional argument to gcc ; perhaps try to compile with
gcc -Wall -g temp.c -lsctp -o temp
Once your program is debugged with the help of the gdb debugger and you consider it to be bug-free, you may ask the compiler to optimize it using
gcc -Wall -O2 temp.c -lsctp -o temp
The order of program arguments to gcc is important and significant.
centos: yum install lksctp-tools-devel
I successfully ran sudo apt-get install libncurses5-dev
Within my Eclipse window I then try to build the following HelloWord.cpp program:
#include <ncurses.h>
int main()
{
initscr(); /* Start curses mode */
printw("Hello World !!!"); /* Print Hello World */
refresh(); /* Print it on to the real screen */
getch(); /* Wait for user input */
endwin(); /* End curses mode */
return 0;
}
I get the following error:
Invoking: GCC C++ Linker
g++ -m32 -lncurses -L/opt/lib -o "Test_V" ./src/curseTest.o ./src/trajectory.o ./src/xJus-epos.o -lEposCmd
/usr/bin/ld: cannot find -lncurses
collect2: error: ld returned 1 exit status
make: *** [Test_V] Error 1
It looks like the compiler is searching for the ncurses library and can't find it? I checked /usr/lib and the library does not exist there so do I need to manually link the ncurses library there - I thought the get-apt installer would automatically do this?
g++ HelloWorld.cpp -lncurses -o HelloWolrd
If you have a 32-bit machine, gcc compile m32 auto. If you have a 64-bit machine and you want to compile 32bits you
Your arguments are not in the correct order. You must specify all source files first and then linker search directories before specifying the libraries to link with. Your command should be like this:
g++ HelloWorld.o -L/opt/lib -lncurses -o HelloWorld
Taken from comment by #ChrisDodd:
Your options are in the wrong order -- -L must be BEFORE -l and both must be after all .o