In a fresh Alpine Linux I installed GCC by
apk add --update-cache gcc
but still a simple program
#include <stdio.h>
int main(int argc, char *argv[]) {
return 0;
}
compiled with message
fatal error: stdio.h: No such file or directory
Install musl-dev (in addition to the gcc compiler)
apk add musl-dev
You need to install it separately because in Alpine Linux, the package GCC doesn't depend on libc-dev for good reason:
You can use gcc to compile things without libc, for example hypervisors firmware etc.
And August Klein also noted that in Debian, GCC only recommends libc-dev for the same reason (but most people don't do --no-install-recommends anyway).
Related
I am using Mac OS X Sierra, and I found that clang (LLVM version 8.1.0 (clang-802.0.38)) does not support OpenMP:
when I run clang -fopenmp program_name.c, I got the following error:
clang: error: unsupported option '-fopenmp'
It seems that clang does not support -fopenmp flag.
I could not find any openmp library in homebrew. According to LLVM website, LLVM already supports OpenMP. But I could not find a way to enable it during compiling.
Does this mean that the default clang in Mac does not support OpenMP?
Could you provide any suggestions?
(When I switch to GCC to compile the same program (gcc is installed using brew install gcc --without-multilib), and the compilation is successful.)
Try using Homebrew's llvm:
brew install llvm
You then have all the llvm binaries in /usr/local/opt/llvm/bin.
Compile the OpenMP Hello World program. Put omp_hello.c
/******************************************************************************
* FILE: omp_hello.c
* DESCRIPTION:
* OpenMP Example - Hello World - C/C++ Version
* In this simple example, the master thread forks a parallel region.
* All threads in the team obtain their unique thread number and print it.
* The master thread only prints the total number of threads. Two OpenMP
* library routines are used to obtain the number of threads and each
* thread's number.
* AUTHOR: Blaise Barney 5/99
* LAST REVISED: 04/06/05
******************************************************************************/
#include <omp.h>
#include <stdio.h>
#include <stdlib.h>
int main (int argc, char *argv[])
{
int nthreads, tid;
/* Fork a team of threads giving them their own copies of variables */
#pragma omp parallel private(nthreads, tid)
{
/* Obtain thread number */
tid = omp_get_thread_num();
printf("Hello World from thread = %d\n", tid);
/* Only master thread does this */
if (tid == 0)
{
nthreads = omp_get_num_threads();
printf("Number of threads = %d\n", nthreads);
}
} /* All threads join master thread and disband */
}
in a file and use:
/usr/local/opt/llvm/bin/clang -fopenmp -L/usr/local/opt/llvm/lib omp_hello.c -o hello
You might also have to set the CPPFLAGS with -I/usr/local/opt/llvm/include.
The makefile should look like this:
CPP = /usr/local/opt/llvm/bin/clang
CPPFLAGS = -I/usr/local/opt/llvm/include -fopenmp
LDFLAGS = -L/usr/local/opt/llvm/lib
omp_hello: omp_hello.c
$(CPP) $(CPPFLAGS) $^ -o $# $(LDFLAGS)
Update
In macOS 10.14 (Mojave) you might get an error like
/usr/local/Cellar/llvm/7.0.1/lib/clang/7.0.1/include/omp.h:118:13: fatal error: 'stdlib.h' file not found
If this happens, the macOS SDK headers are missing from /usr/include. They moved into the SDK itself with Xcode 10. Install the headers into /usr/include with
open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg
Other people have given one solution (using Homebrew llvm). You can also use OpenMP with Apple Clang and Homebrew libomp (brew install libomp). Just replace a command like clang -fopenmp test.c with clang -Xpreprocessor -fopenmp test.c -lomp.
MacOS Mojave with CMake
Install LLVM with openmp and libomp with brew
brew update
brew install llvm libomp
add include directories and link directories in CMakeList.txt
include_directories("/usr/local/include" "/usr/local/opt/llvm/include")
link_directories("/usr/local/lib" "/usr/local/opt/llvm/lib")
run CMake with the new compilers
cmake -DCMAKE_C_COMPILER="/usr/local/opt/llvm/bin/clang" -DCMAKE_CXX_COMPILER="/usr/local/opt/llvm/bin/clang++" ..
The clang version is 7.0.1 at time of writing
Conda-Based Compilation Environment
Conda uses clang for OSX compilation (umbrella package cxx-compiler), but I hit similar issues with using llvm-openmp and the -fopenmp flag throwing errors. Solution is rather similar to other answers, but I am including here in case others have more exactly this issue.
Specific solution was to include the Conda environment's include/ directory in the CFLAGS, namely:
CFLAGS="-I${CONDA_PREFIX}/include"
Note, I also needed to add -lstdc++ -Wl,-rpath ${CONDA_PREFIX}/lib -L${CONDA_PREFIX}/lib when linking, similar to this GitHub Issue.
when I compile my script with only
#include <mpi.h>
it tells me that there is no such file or directory.
But when i include the path to mpi.h as
#include "/usr/include/mpi/mpi.h"
(the path is correct) it returns:
In file included from /usr/include/mpi/mpi.h:2087:0,
from lbm.cc:7:
/usr/include/mpi/openmpi/ompi/mpi/cxx/mpicxx.h:35:17: fatal error: mpi.h: No such file or directory
#include "mpi.h"
^
compilation terminated.
Anyone know how to fix this?
The problem is almost certainly that you're not using the MPI compiler wrappers. Whenever you're compiling an MPI program, you should use the MPI wrappers:
C - mpicc
C++ - mpiCC, mpicxx, mpic++
FORTRAN - mpifort, mpif77, mpif90
These wrappers do all of the dirty work for you of making sure that all of the appropriate compiler flags, libraries, include directories, library directories, etc. are included when you compile your program.
On my system, I was just missing the Linux package.
sudo apt install libopenmpi-dev
pip install mpi4py
(example of something that uses it that is a good instant test to see if it succeeded)
Succeded.
You can execute:
$ mpicc -showme
result :
gcc -I/Users/<USER_NAME>/openmpi-2.0.1/include -L/Users/<USER_NAME>/openmpi-2.0.1/lib -lmp
This command shows you the necessary libraries to compile mpicc
Example:
$ mpicc -g -I/Users/<USER_NAME>/openmpi-2.0.1/include -o [nameExec] [objetcs.o...] [program.c] -lm
$ mpicc -g -I/Users/<USER_NAME>/openmpi-2.0.1/include -o example file_object.o my_program.c otherlib.o -lm
this command generates executable with your program in example, you can execute :
$ ./example
On my system Ubuntu 16.04. I installed :
sudo apt install libopenmpi-dev
after I used mpiCC to compile and it works
As suggested above the inclusion of
/usr/lib/openmpi/include
in the include path takes care of this (in my case)
Debian appears to include the following:
mpiCC.openmpi
mpic++.openmpi
mpicc.openmpi
mpicxx.openmpi
mpif77.openmpi
mpif90.openmpi
I'll test symlinks of each for mpic, etc., and see if that helps the likes of HDF5-openmpi enabled find mpi.h.
Take that back Debian includes symlinks via their alternatives system and it still cannot find the proper paths between HDF5 openmpi packages and mpi.h referenced in the H5public.h header.
On Ubuntu 18.04 I had to install:
sudo apt install lam4-dev
On Fedora:
dnf install openmpi-devel
On Mac 12.2, I installed with brew install openmpi. The header file is under /opt/homebrew/Cellar/open-mpi/x.x.x/include.
once you have mpi installed:
$ sudo apt install mpich
see where the library is installed, each case is different:
$ mpicc -show
in my case: (Ubuntu 20.0)
and add...
#include </usr/lib/x86_64-linux-gnu/openmpi/include/openmpi>
:-)
I have this minimal example:
QT -= gui
CONFIG += qt console
SOURCES += main.cpp
#include <QDebug>
int main(int argc, char** argv)
{
return 0;
}
which gives this link error when building the project:
c:/qtsdk/mingw/bin/../lib/gcc/mingw32/4.4.0/../../../../mingw32/bin/ld.exe: final link failed: Invalid argument
The link command looks like this:
g++ -Wl -Wl -Wl,-subsystem,console -mthreads -o debug\test.exe debug/main.o -L"c:\QtSDK\Desktop\Qt\4.8.1\mingw\lib" -lQtCored4
My setup:
Windows XP SP3
Qt SDK version 1.2.1 (QtCreator 2.4.1, Qt Desktop version 4.8.1) (fresh install at C:\QtSDK\)
MinGW32 version 4.4.0 (included in Qt SDK at C:\QtSDK\mingw\)
If I remove the #include <QDebug>, it compiles fine. If I include some other Qt header file, like for example QCoreApplication, it compiles fine, too.
EDIT: Here is a very strange minimal example. Consider an empty main function like above. Now if i put these includes, it fails to link:
#include <QWidget>
#include <QVariant>
But if I remove one of them, it links without an error.
What's the problem? Why doesn't mingw tell me what the invalid argument is?
Im wondering is the linker could not find the lQtCored4 lib? Is it actually in the -L directory?
For a week I've been struggling with compiling openCV programs. I've tried everything I could possibly find on the internet.
What I did is: I've downloaded OpenCV-2.3.1-win-superpack.exe and followed this official installation guide.
In the CMake (gui) my source was: D:\opencv and build destination was: C:\opencv.
I've also added C:\opencv\install\bin;C:\opencv\bin to my system's PATH variable.
What I want is to compile openCV programs on my Windows OS using MinGW's gcc/g++ compilers.
I've tried various gcc/g++ parameters that I've found on the internet and days playing with the -I and -L options the compiler can never find the openCV functions or structures.
What I am trying to compile:
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <cv.h>
#include <highgui.h>
int main(int argc, char *argv[])
{
// Nothing but create a window
cvNamedWindow("mainWin", CV_WINDOW_AUTOSIZE);
cvMoveWindow("mainWin", 100, 100);
cvWaitKey(0);
return 0;
}
Error:
Input:
gcc test.c -o test -I"C:\opencv\install\include" -I"C:\opencv\install\include\opencv" -L"C:\opencv\install\bin"
Output:
...\ccK4MfHv.o:test.c:(.text+0xa0b): undefined reference to `cvFree_'
Or with g++:
Input:
g++ test.c -o test -I"C:\opencv\install\include" -I"C:\opencv\install\include\opencv" -L"C:\opencv\install\bin"
Output:
...\ccXCTKa1.o:test.c:(.text+0x1e): undefined reference to `cvNamedWindow'
Side note: trying to compile in VS2005 I get the same error.
Thank you for your time!
In case someone else needs to solve this issue, here's how I got the posted OpenCV/HighGUI sample code to compile in Windows 7 x64 using MinGW, MSYS, and CMake:
build OpenCV from source using MinGW/MSYS/CMake. This is because I could not get the MinGW compiled version in the OpenCV-win-SuperPack to link properly in MinGW/MSYS/Windows 7 x64.
For full reference, here's how I compiled OpenCV:
make sure you have an up-to-date CMake (v2.6 or later) and MinGW (with GCC, G++, and MSYS options) installed
if you want the new Qt-based OpenCV HighGUI front-end, you will need to install Qt 4 (SDK).
download a OpenCV source/superpack version 2.2 or later (I used OpenCV-2.3.1-win-superpack.exe)
unzip the contents to [OPENCV_SOURCE_DIR] (I put it in C:/opencv, so there should be a file at C:/opencv/README for example)
create a [OPENCV_BUILD_DIR] directory elsewhere (I used C:/opencv/build/mingw)
use the CMake-GUI tool, specify the source directory as [OPENCV_SOURCE_DIR], the build directory as [OPENCV_BUILD_DIR], and click "Configure".
you may wish/need to go tweak the options (e.g. I ticked "Qt" and "Qt-OpenGL" entries, then clicked "Configure" again, then had to provide the path to the qmake executable)
once you have finished configuring OpenCV, click "Generate"
in a MSYS terminal, browse to [OPENCV_BUILD_DIR], and run "make" to build the code (this may take a while)
once the has been built properly, run "make install", which collects the built code/libraries/include dirs into [OPENCV_BUILD_DIR]/install folder (or a different folder if you changed the corresponding option when using the CMake-GUI tool)
add [OPENCV_BUILD_DIR]/install/bin folder to the PATH environmental variable. If you do not know how to do this, then I'd recommend using the Path Editor GUI tool.
if you end up using Qt, you will also need to put the bin folder of Qt SDK in the PATH environmental variable. This is the folder that includes qmake.exe.
put the following sample code into a file called test.c. I modified the includes slightly to make them compatible with OpenCV v2.2 and above.
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <opencv/cv.h>
#include <opencv/highgui.h>
int main(int argc, char *argv[])
{
// Nothing but create a window
cvNamedWindow("mainWin", CV_WINDOW_AUTOSIZE);
cvMoveWindow("mainWin", 100, 100);
cvWaitKey(0);
return 0;
}
in a MSYS terminal, browse to the folder where you put test.c, and run:
gcc -o test -I"[OPENCV_BUILD_DIR]/install/include" test.c \
-L"[OPENCV_BUILD_DIR]/install/lib" \
-lopencv_core[OPENCV_VERSION] \
-lopencv_imgproc[OPENCV_VERSION] \
-lopencv_highgui[OPENCV_VERSION]
So in my case:
gcc -o test -I"/c/opencv/build/mingw/install/include" test.c \
-L"/c/opencv/build/mingw/install/lib" \
-lopencv_core231
-lopencv_imgproc231
-lopencv_highgui231
Path Editor: http://www.redfernplace.com/software-projects/patheditor/
You have the directory, C:\opencv\install\bin, to locate libraries on the gcc/g++ command line, but I think you'll also need to specify the libraries to use as linker inputs as well. I'm not sure what libraries are part of the OpenCV distribution, but going by the example on the instruction page you linked to, one might be:
-lopencv_calib3d220.dll
You'll probably have to add one or more other ones (that follow the name pattern lib*.a in the C:\opencv\install\bin directory - or maybe some other lib directory that you should be passing in a -L option).
I'm a bit of an AIX newbie. I'm trying to compile a program using gcc's stack protector feature. I installed gcc on server using pware's GCC package and I can compile a sample program like:
#include <stdio.h>
int main(int argc,char **argv)
{
printf("hello world\n");
return 0;
}
When I turn on stack-protector though, I get:
g++ -fstack-protector-all main.cpp
collect2: library libssp_nonshared not found
I've been hunting on google for a solution to this and it seems like my libc needs to have some stuff built into that mine doesn't. Is there a package out there that includes a libc with the stack protection builtin?
g++ -v returns
Using built-in specs.
Target: powerpc-ibm-aix5.3.0.0
Configured with: ../stage/gcc-4.2.4/configure --disable-shared --enable-threads=posix --prefix=/opt/pware --with-long-double-128 --with-mpfr=/opt/pware --with-gmp=/opt/pware
Thread model: aix
gcc version 4.2.4
I can not find libssp_nonshared.a on the system -- is there an additional package I need to install or should it have come with the gcc package?
This has nothing to do with libc: your GCC installation is missing libssp_nonshared.a library.
What does your "gcc --version" say? It may have been configured with --disable-libssp option (in which case you can't use the stack protection instrumentation).
Update:
I just looked in gcc-4.3.0/configure:
powerpc-*-aix*)
noconfigdirs="$noconfigdirs gprof target-libgloss target-libssp ${libgcj}"
;;
I am about 99% sure this means that libssp (and therefore -fstack-protector) is not available for your platform. Sorry :-(