how to compile g++ app and run anywhere? - linux

my program compiled and worked fine with:
g++ main.cpp exm1.cpp exm2.cpp -o main.o
i want to compile this app and run anywhere
how can i?
i try this code
g++ -g -Wall -I/MyApp/lib -static-libgcc -static-libstdc++ -static main.cpp exm1.cpp exm2.cpp -o main.o
but not work
in lib folder has 2 files:
exm1.h
exm2.h
main.cpp included:
#include <fstream>
#include <iostream>
#include <string>
#include <streambuf>
#include <stdlib.h>
#include "lib/exm1.h"
#include "lib/exm2.h"
my linux is kali, and i want run this app on CentOS 6
please help me,thanks

As C. bear said, use the -m32 flag so the program is able to run on 64- and 32- bit systems. In doing this, You'll also have to install the 32bit stdlibs. I'm not sure how to do this on kali, give it a google. Another thing you can do to avoid having users install external libraries (if you use them at any point) is to statically link you executable. Use the -static flag to do this. However, because all your app's dependencies (including the stdlibs) will be in a single file, it will get pretty big. On the other hand, loading times will be better, because your app doesn't have to run the dynamic linker and wait for it to link your external libraries as you call them.

So from comments one reason could be you executable is 64-bit and centOS a 32-bit sytem. Try compilation with -m32 flag.

how to compile g++ app and run anywhere?
It is not easily possible. For example, an ELF executable produced by GCC on a recent Debian/x86-64 computer won't run on a RaspberryPi (with a linux for ARM 32 bits, e.g. some Raspbian)
Read more about execve(2), elf(5) and about fat binaries
Be aware that the GCC compiler suite can be built (from its source code) as a cross-compiler (but you'll need to rebuild GCC for every different target system).
I recommend to invoke GCC as g++ -Wall -Wextra -g during the debugging phase (and use GDB). Once your software is debugged, compile it with g++ -Wall -Wextra -O2 to get an optimized binary (or even compile and link it with g++ -Wall -Wextra -O3 -flto)

Related

Source-built clang-3.7 on Linux not finding Block_copy

I built and installed llvm/clang-3.7 from source on my Ubuntu Linux system (I'm building from source because my development environment at work does not have apt-get available). The gcc version is 4.8.2. I followed the clang build instructions at http://clang.llvm.org/get_started.html, and everything worked fine (mkdir build; cd build; cmake -G "Unix Makefiles" ../llvm; make; make install). However, I'm now finding that a program to test Block_copy fails to compile. The program is auto-generated by autoconf when I try to build gnustep-base. The part that fails is:
int
main ()
{
return _Block_copy ();
;
return 0;
}
My compile command is:
clang -o conftest -m64 -march=opteron -mno-3dnow -ggdb -O2 -Wall -I/home/build/GNUstep/Local/Library/Headers -I/home/build/GNUstep/Local/Library/Headers -I/home/build/GNUstep/System/Library/Headers -fgnu-runtime -x objective-c -m64 -L/home/build/GNUstep/Local/Library/Libraries -L/home/build/GNUstep/Local/Library/Libraries -L/home/build/GNUstep/System/Library/Libraries conftest.c -lrt -ldl -lpthread -rdynamic -m64 -fgnu-runtime -L/home/build/GNUstep/Library/Libraries -L/home/build/GNUstep/Local/Library/Libraries -L/home/build/GNUstep/System/Library/Libraries -lobjc -lm
Do I need to build clang with a special option to enable blocks, or should I be linking with another library?
Do I need to build clang with a special option to enable blocks
No. But you may need -fblocks option using the clang binary.
-fblocks
Enable the "Blocks" language feature.
should I be linking with another library?
AFAIK, Yes.
_Block_copy is a part of BlocksRuntime.
BlocksRuntime Block.h
BlocksRuntime runtime.c
Have you compiled compiler-rt? It includes BlocksRuntime. The document explains how to build compiler-rt.

gcc 4.8.2 on Linux - Simple program using thread crashes

I have just installed gcc 4.8.2 on Centos (I am using devtoolset-2). I wrote a very simple program using thread. It compiles fine but crashes when executed?
#include <thread>
#include <iostream>
void test()
{
std::cout << "test\n";
}
void main()
{
std::thread t(test);
t.join();
return 0;
}
I compile with:
scl enable devtoolset-2 bash
c++ -o test test.cpp -std=c++11
I am terribly surprised. I must do something wrong, not using the write libc++ etc? Do you have any idea how I could debug this. Thank you!
I compile it on Mac (Maverick) which obviously doesn't use gcc and it works fine.
On Linux, you should use the command line option -pthread with GCC and Clang for compiling and linking. In your case, the command line should look as follows:
g++ -std=c++11 -Wall -Wextra -pthread test.cpp -o test
See the following links for more information:
https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_concurrency.html
gcc - significance of -pthread flag when compiling
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52681

OMP Cross compilation with x86_64-w64-mingw32-g++

I have some trouble with crosscompiling C++ program which takes advantage of openMP library. I am using Linux Ubuntu 12.04 LTS. I want to obtain executable file runnable on Windows.
I have no problem with compiling my program with OMP with regular g++ command:
g++ a.cpp b.cpp -o OMPres -pg -O3 -I./CBLAS/include -L./ -lcblas
Also when I try crosscompilation without OMP, everything runs perfectly fine:
x86_64-w64-mingw32-g++ a.cpp b.cpp -O3 -I./CBLAS/include ./CBLAS/cblas_WIN64.a ./BLAS/blas_WIN64.a -o res.exe -l gfortran -static
But when I try to crosscompile it with OMP using following command:
x86_64-w64-mingw32-g++ a.cpp b.cpp -O3 -I./CBLAS/include ./CBLAS/cblas_WIN64.a ./BLAS/blas_WIN64.a -o OMPres.exe -l gfortran -static -fopenmp
I get this error:
a.cpp:41:17: fatal error: omp.h: No such file or directory
compilation terminated.
I found where omp.h file is located on my disk, and added the path to the command. After executing it:
x86_64-w64-mingw32-g++ a.cpp b.cpp -O3 -I./CBLAS/include -I/usr/lib/gcc/x86_64-linux-gnu/4.6/include ./CBLAS/cblas_WIN64.a ./BLAS/blas_WIN64.a -o OMPres.exe -l gfortran -static -fopenmp
I got another error: x86_64-w64-mingw32-g++: error: libgomp.spec: No such file or directory
As I also have this file on the disk I tried to copy it in various places and finaly it worked when I copied it directly into the directory where compilation takes place. Then it produced another error:
/usr/bin/x86_64-w64-mingw32-ld: cannot find -lgomp
/usr/bin/x86_64-w64-mingw32-ld: cannot find -lrt
collect2: ld returned 1 exit status
I don't have a good understanding of how compilers exactly work. I tried to update all mingw-w64 compilers that I could find with apt-cache search but nothing helped. I have no idea what more I can do :(.
First, #nmaier is completely correct in that the Ubuntu x86_64-w64-mingw32 toolchain is crippled, and that you can rebuild the toolchain yourself.
I, however, suggest that you use MXE, which saves you the time of manually compiling gcc and every dependency of it. The steps below should be enough for your purpose:
# Get MXE
git clone https://github.com/mxe/mxe.git && cd mxe
# Settings
cat <<EOF > settings.mk
MXE_TARGETS := x86_64-w64-mingw32.static
JOBS := 4
EOF
# Build gcc, libgomp, blas, and cblas. It will take a while
make -j2 libgomp cblas
# Add toolchain to PATH
# See http://htmlpreview.github.io/?https://github.com/mxe/mxe/blob/master/index.html#tutorial step 4
export PATH=`pwd`/usr/bin:$PATH
# You don't need -I./CBLAS/include ./CBLAS/cblas_WIN64.a ./BLAS/blas_WIN64.a
# because headers and libraries are installed to standard location and
# I already used `-lcblas -lblas`.
x86_64-w64-mingw32-g++ a.cpp b.cpp -fopenmp -O3 -o res.exe -lcblas -lblas -lgfortran -lquadmath
Your x86_64-w64-mingw32 toolchain appears to have been build without libgomp.
You could check your supplier/distribution if it there additional or variant packages that have libgomp.
Or switch to a different supplier/distribution.
Or you could rebuild (or build in the first place) a cross gcc with --enable-libgomp. This is kinda the hard way.
PS:
Adding paths that do not correspond with your platform, like -I/usr/lib/gcc/x86_64-linux-gnu/4.6/include, is a bad idea in general, and will most certainly fail... This kinda creates a Franken-compiler.

How to make gcc link libssp statically?

How can I get GCC to use that static library instead of the dynamic one? Normally you add the .a file to the linker parameters. But libssp linking is triggered by the -fstack-protector option. And compiler prefers linking to the shared library if it finds one instead of static library.
If I try to run the resulting program on systems that don't have the libssp.so the program won't run.
(After system upgrade on some build machines, the older boxes on the test system screwed up)
Does
gcc -static static.c -o static -fstack-protector-all
or
gcc -static -lssp static.c -o static -fstack-protector-all
work? Can you run ldd on the resulting binaries?
What version of gcc are you using?

"cmath: No such file or directory" when compiled with GCC

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.

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