I'm using ortools in c++ to model a vehicle routing problem. I was wondering whether there was a way to compile the code using my own Makefile by including the proper flags for the compiler, so that I don't have to use
make build SOURCE=/path/to/my/program
I have compiled ortools from source on Debian 10, making sure to follow the proper instructions on the guide (make third-party then make cc then make install_cc). make test_cc runs and finished without problems, so I don't think there is any issues with the installation.
The only clue that I found about this topic was someone writing they used
g++ -std=c++11 -o my_program my_program.cc -I/usr/local/include/or-tools -lortools
to compile their program, but upon trying that, I have a lot of undefined references. I have read somewhere that one should use -std=c++17 instead of -std=c++11 but either way it does not work.
Please let me know if you need more details.
All binary packages comes with a supplied makefile.
You can see the source here: https://github.com/google/or-tools/blob/stable/tools/Makefile.cc.java.dotnet
If you run make detect_cc. It will print out all compiling and linking options for your platform.
Since ortools is a shared library, you will have to specify its path using the environment variable LD_LIBRARY_PATH in addition to specifying the path using the -L flag.
export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:<path-to-lib>.
You can put the export command above in the .bashrc file or run it every time your run the code. Also, you will have to used C++17.
Related
I am trying to statically cross-compile an Application for ARM using the Linaro-Toolchain 7.1.1 . The final elf file is dependent on two shared-objects. I need to statically compile the application because there are dependencies that are not available on my target-system (eg. libstdc++). The -L and -I flags are in the makefile and everything works normally without the -static Flag. However when i use the -static flag, my linaro-linker tells me that it cannot find the dependencies, even though i know they are there as liba.so and libb.so. Any help or point to literature is appreciated, i feel like i did not fully understand what -static does, eventhough i did my research online.
Thanks
Thanks to your comments i was able to solve my problem and understand why i had it.
As user RPGillespie mentioned, the -static flag needs archived (libx.a) versions of the objects, so i had to compile the .o files to .a files using the ar-tool from the linaro toolchain.
Furthermore, as user RPGillespie refered me to, i had to specify the archives x using -l:libx.a instead of -lx in the g++ command.
Also it took me some time to notice that if the x.a files are not present, the linker will link dynamically. In my makefile the executable was compiled before the x.a file was available (because i just modified the makefile used to build the x.so).
I am running a code (iHARM2D) which requires the GNU scientific library library (GSL) on a cluster. Since the GSL library is not installed on the cluster, I have to compile it there and properly link it during compilation of the actual code. In my shell script I write
cd whereGSLsource
./configure --prefix=/homefolder/iHARM/GSLcompiled
make && make install
This compiles the GSL and puts the results in /homefolder/iHARM/GSLcompiled/lib, /homefolder/iHARM/GSLcompiled/include etc.
According to this answer, I should be able to compile by writing the following lines into my shell script before compilation of my main code
export CPATH="/homefolder/iHARM/GSLcompiled/include":$CPATH
export LIBRARY_PATH="/homefolder/iHARM/GSLcompiled/lib":$LIBRARY_PATH
However, this does not seem to link GSL properly because the compilation returns errors of the type "undefined reference to `gsl_some_function'". (It works on my computer when default installation and linking of GSL is used.)
Another possibility suggested by the GSL output during compilation or this answer is to modify the LD_LIBRARY_PATH variable
LD_LIBRARY_PATH="/homefolder/iHARM/GSLcompiled/lib":$LD_LIBRARY_PATH
But this gives the same result. Similarly it does not when I try to link using the -L and -I option
cd iHARM
gcc -someoptions -I../GSLcompiled/include/ -L../GSLcompiled/lib ./some.o -o harm
Another option suggested by GSL was to use
gcc -someoptions -Wl,-rpath -Wl,"/homefolder/iHARM/GSLcompiled/lib" ./some.o -o harm
However, neither of these work.
How do I link the GSL properly then?
(I am not very experienced in this so this might also be some really basic mistake in the syntax or so.)
Run first configure --help; you'll find out that it accepts the --enable-static option which you do want to use.
BTW you could (and probably should) install Linux on your laptop and compile on it (then scp a mostly statically linked binary to your cluster).
You'll better share a common --prefix for all your autoconf-ed software. See this. Read the documentation of autoconf. Let's suppose you always use --prefix=$HOME/soft (which don't require any root permission).
You could compile with make then do a make install DESTDIR=/tmp/gslinst so that installed things go into /tmp/gslinst which you would inspect and latter copy appropriately to a directory related to your prefix.
You'll find both libgsl.a and libgslcblas.a. On my Debian system, the libgsl-dev package provides them (so I don't need to rebuild it).
Then you'll use these static libraries. You could provide a full path for them, that is use $HOME/soft/lib/libgsl.a explicitly in your linking gcc command for harm, e.g. link it with
gcc some.o $HOME/soft/lib/libgsl.a -o harm
but YMMV. Order of arguments to gcc matters a lot.
You don't need or want to mess with $LD_LIBRARY_PATH or -Wl,-rpath with static linking. Read about rpath when you want dynamic linking.
See also what pkg-config tells.
I have a code on my computer uses Petsc which depends on mpi. On my computer it works well. I put it on cluster, exported paths of gcc, Petsc and openmpi (although I was using mpich on my computer I hope openmpi will also work) to LD_LIBRARY_PATH and PATH. I also changed paths in makefile. Petsc, gcc, openmpi were all available on cluster so I did not configure anything. When I did make, compiler gave error:
fatal error: mpi.h: No such file or directory
I know I did not give complete information but I can tell more if needed. How can I make the Petsc to know where is mpi.h?
Typically, you should use mpicc (or mpicxx for C++) to compile instead of gcc (or g++ for C++). These commands are simple wrappers around gcc and g++ that simply add in the appropriate -I/path/to/mpi/includes and -L/path/to/mpi/libs automatically and should be included with your openmpi install. In the absence of that, simply add -I/path/to/mpi/includes in your command to compile the appropriate files. This tells the compiler where to look for the appropriate header files.
To answer the question. To prevent a C/C++ editor from showing errors as you tyoe in the "special code" just use:
#include </usr/include/mpi/mpi.h>
which seems to be a link -- but doing that turns off the errors in Netbeans editor so I can code without distraction.
Note: Using Ubuntu 18.04 Desktop as editing machine -- and testing run machine -- but I compile manually using mpic as noted previously.
sudo mpicc c_pi.c -o c_pi
and then...
mpiexec ./c_pi
hth
So I'm using Anaconda to run Python 2.7 32-bit on my company's server. That works dandy. Anaconda came with MinGW, so I'm attempting to use the g++ compiler in there. Everything works for me. I can compile c++ source, and then run the resulting executable. The issue comes when coworkers try to do the same. Apparently, the g++ compiler creates a dependency for the executable it makes on a particular dll located within Anaconda. I have a path variable to where this dll lives, my coworkers do not, thus, they cannot run any executable made by g++.
Is there a way to specify where this dll dependency is when I compile executable so that anyone can use them? Something like:
g++ someCode.cpp -o someCode.exe locationOfDll=path2dll
Just to be clear, everyone can successfully compile c++ source code, but only I can run the resulting executable. Thanks in advance
EDIT: I forgot to mention that simply giving everyone the path variable is not an option.
Does this help? It discusses updating the library search paths.
http://www.mingw.org/wiki/HOWTO_Specify_the_Location_of_Libraries_for_use_with_MinGW
I know how to use g++ and all that to compile c++ programs.
My question is, if I have some code which depends on various libraries, how can I compile it into a simple executable that I can send anyone. For this I would be happy with just keeping it on os x.
I would like to know how to compile a "real" program not just an executable I can run locally.
I have tried googling this but haven't found much.
Do I have to use installing software?
I know in windows you can make some simple .exe stuff that use common DLL files.
You a looking for "static linking". That will import all the needed code from the libraries into your executable. Note the executable will get larger. If you are using standard libraries, they should be present on standard OS installation.
You should try "-static" flag of g++.
Running "ldd your_executable_name" should display all libraries your executable uses (linked dynamically).
Since you are talking about Mac OS X, you probably want to make a bundle. Qt Software has a very useful deployment guide for getting started with this kind of activity.
You can use -static or -s option for static linking in gcc or g++