It would be helpful if you could provide some guidance on how to compile c++ source code files in an Ubuntu environment, using the MATLAB Engine with g++.
I assume that you want to know the procedure for compiling the c++ code (which calls MATLAB engine) using g++ from Linux Terminal. To do so, follow the steps below:
Include following paths in PATH variable:
a) Location of MATLAB i.e. $matlabroot/bin
b) $matlabroot/sys/os
You can do this by using the command
'setenv PATH $matlabroot/bin:$matlabroot/sys/os:$PATH ' .
In the command prompt, navigate to the directory where the cpp code is located using cd command. For instance, if you are compiling engdemo.cpp, you need to navigate to $matlabroot/extern/examples/eng_mat/engdemo.cpp
You need to call the compiler with required include files and libraries. For this you can use -I and -L switches for that. Note that the order is important. So you need to use the command as below:
g++ engdemo.cpp -I "$matlabroot/extern/include" -L "$matlabroot/bin/glnxa64" -leng -lmat -lmex -lut -o engdemo.o
The above command will generate an object file engdemo.o. To execute this, use the command ./engdemo.o
You can refer to the document at http://www.umiacs.umd.edu/~jsp/Downloads/MatlabEngine/MatlabEngine.pdf for more help regarding C++ and MATLAB.
The compilation process in C/C++ is divided in two phases:
First, the compilation where source code is transformed into machines code with multiples object files (.o or .obj).
Then, the link to transform object files into a single executable file (.dll or .exe).
C/C++ programs that run matlab engine need three things:
1> A compiler that is compatible with matlab engine.
2> Reference to API header files('.h' for c or '.hpp' for c++) for compilation.
3> Reference to the libraries('.lib' for windows,'.so' for linux) for external symbol link.
You can see comptatible linux based system compiler here.
The GCC C/C++ 4.9.x is compatible so you can use g++.
As this pdf suggested, the API header files should be there $matlabroot/extern/include and the .so files should be in $matlabroot/
bin/glnax64 where $matlabroot is your matlab install folder
Set up Environment variables
Open your temnial with ctrl + alt + T and type :
setenv PATH $matlabroot/bin:$matlabroot/sys/os:$PATH
You can then go to the folder where source file is located, let's say $matlabroot/extern/examples/eng_mat/ with the following command :
cd $matlabroot/extern/examples/eng_mat/
You need to do the compilation with :
g++ -c engDemo.cpp -I '$matlabroot/extern/include' -leng -lmat -lmex -lut
After that, a file named engDemo.o should be created.
The -leng -lmat -lmex -lut options are probably needed among other things because of the usage of the matlab interpreter that should be located in $matlabroot/bin
And the external symbol link with :
g++ -o engDemo -L '$matlabroot/bin/glnax64'
Be careful as this path sugested that you are on a x64 architecture machine, if you are not,the path might be slightly different.
Then you can execute your file just by doing ./engDemo
I can't install the matlab engine on the laptot I am using so I'm unable to test the instruction I gave you but It should be done this way.
Hope it helps !!
Related
I'm trying to generate a mex function usigin external libraries. I'm using Ubuntu 18 and Matlab R2021a.
In particular I want to compile my file.cpp that uses my cpp library called model.
What I did is
mex -I<path_library_include> -L<path_library_so_file> -lmodel.so -lboost_system -lstdc++ file.cpp -v
where in -I i put the path where is the include of the library in -L the path in which the libmodel.so is located, then I added 2 more libraries and at the end the source file that I want to compile.
In this way I can compile my source but when I try to execute the mex function I get:
libmodel.so: cannot open shared object file: No such file or directory
I also tested the library outside matlab and works fine, this is the command that I use to compile the library outside Matlab
gcc -Wall -I<path_library_include> -L<path_library_so_file> main.cpp -lmodel -lboost_system -lstdc++ -o main
What could be the problem with Matlab?
Thanks to 273K that gave me the right direction.
The problem was that the LD_LIBRARY_PATH was not configured well in fact running /sbin/ldconfig -v my library was not present. So to add the shared library i created a new file as root in /etc/ld.so.conf.d/ called mylib.conf it is not important the name just the extension. Then I run
sudo ldconfig
after that the library was present in fact running
/sbin/ldconfig -v | grep model
where model is the name of my library. it is possible to see the output.
I'm trying to compile C++ on Windows.
The command needed to compile on Linux is:
g++ -O3 -Wall -shared -std=c++11 -fPIC `python -m pybind11 --includes` EO_functions_bipartite.cpp -o extremal_bi.so
I installed MinGW but when I try to compile I get the following error:
g++.exe: error: python: No such file or directory
g++.exe: error: pybind11: No such file or directory
g++.exe: error: unrecognized command line option '-m'
g++.exe: error: unrecognized command line option '--includes EO_functions_bipartite.cpp'
g++.exe: fatal error: no input files
compilation terminated.
Assuming you have python in your path.
The backtick escape thing that embeds the python -m pybind11 --includes command within the g++ doesn't work on cmd.exe in Windows.
Run the python -m pybind11 --includes command on its own line in the cmd shell. Take the output of that command and substitute in into the g++ command. It should be a bunch of -I include params.
So if the output of the python command is this:
-IC:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.7_3.7.2544.0_x64__qbz5n2kfra8p0\Include -IC:\Users\User\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.7_qbz5n2kfra8p0\LocalCache\local-packages\Python37\site-packages\pybind11\include
Expand your g++ command to be this:
g++ -O3 -Wall -shared -std=c++11 -fPIC "-IC:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.7_3.7.2544.0_x64__qbz5n2kfra8p0\Include" -IC:\Users\User\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.7_qbz5n2kfra8p0\LocalCache\local-packages\Python37\site-packages\pybind11\include EO_functions_bipartite.cpp -o extremal_bi.so
Notice the quotes I put around the first include directory because it has a space in its path.
The easiest way to start on native Windows if you have a Linux background is to install MSYS2 shell with MinGW-w64. This will provide an actual bash that allows you to run commands almost exactly the same way as on Linux, including support for backticks like in the case of your issue.
Though I would always recommend using $( ... ) instead of backticks, as this allows nesting.
Note that MinGW-w64 also exists on Windows to allow cross-building for Windows from Linux, but that may be a bit more difficult if you have never done any cross-building before.
Also -shared ... -o extremal_bi.so in your command should be replaced with -shared ... -o extremal_bi.dll -Wl,--out-implib,libextremal_bi.dll.a as .so files don't exist on Windows as Windows uses .dll files for shared libraries and the compiler uses .dll.a files as library objects for them.
Finally on Windows you need to tell the compiler or linker which symbols you will be exporting by either writing a libextremal_bi.def starting with the line EXPORTS followed all the symbols you want to be exported and include -def libextremal_bi.def in the link command, or using __declspec(dllexport)/__declspec(dllimport) when defining those symbols, which may be a bit complexer as it requires some conditional defines to determine if the code is being compiled for Windows and if it's during the actual build process of the shared library (__declspec(dllexport)) or code that uses it (__declspec(dllimport)). There is also another method to export all symbols, but that's a dirty method that may more easily cause symbol conflicts.
Good Day Everyone,
N.B - This problem has been solved - I have provided my own solution in the answer section however the solution provided by Jonathan is much shorter. Nevertheless, this was the following question I originally posted:
I am basically trying to compile a serial library (for UART communication) on Linux however I am not really sure how to correctly compile (I have mentioned what I have done so far below), any suggestions would be highly valuable. I am using the serialib library - which is composed of 2 main files (serialib.h and serialib.cpp) , you may directly view the source code of these files here (scroll all the way to the bottom and view the files in new tabs): http://serialib.free.fr/html/classserialib.html
I transferred these files (serialib.h and serialib.cpp) to my BeagleBone Black micro-controller which is running Debian (Wheezy) , g++/gcc (Debian 4.6.3-14) 4.6.3. I wrote my own program (uart.cpp is my file name) to access the functions provided by this library, this is what I wrote:
#include <iostream>
#include "serialib.h"
#ifdef __linux__
#define DEVICE_PORT "/dev/ttyO1"
#endif
int main()
{
serialib LS;
return 0;
}
So as you can see I am trying to access the 'seriallib' class. serialib.h, serialib.cpp and uart.cpp are all in the home directory. I also manually added the iostream library in serialib.cpp as I did not see it being declared in the original source code.
Now I am really unsure of how to compile such external libraries but so far I tried the following steps:
g++ -c -Wall -Werror -fPIC serialib.c to convert to PIC which gives the following error:
distcc[3142] (dcc_parse_hosts) Warning: /home/debian/.distcc/zeroconf/hosts contained no hosts; can't distribute work
distcc[3142] (dcc_zeroconf_add_hosts) CRITICAL! failed to parse host file.
distcc[3142] (dcc_build_somewhere) Warning: failed to distribute, running locally instead
g++ serialib.cpp -L /home/debian/serialib.h which gives the following error:
/usr/lib/gcc/arm-linux-gnueabihf/4.6/../../../arm-linux-gnueabihf/crt1.o: In function _start':
(.text+0x30): undefined reference tomain'
collect2: ld returned 1 exit status
distcc[3210] ERROR: compile serialib.cpp on localhost failed
As of now I am still finding out how to compile this and if I manage to work this out then I'll post my solution here too. Once again any suggestion will be highly valuable. Thank you all :) .
g++ -c -Wall -Werror -fPIC serialib.c to convert to PIC which gives the following error:
The "error" is not an error, it's a warning, telling you that your distcc setup is broken, but that it compiled locally.
That command doesn't "convert to PIC", it compiles the file serialib.c and produces a compiled object file, serialib.o
g++ serialib.cpp -L /home/debian/serialib.h
This is just nonsense. It tries to build a program from serialib.cpp and use the directory /home/debian/serialib.h (which isn't a directory!) to find libraries.
You don't need to "compile a library" you can just compile both the source files and link them together into a program. Either:
g++ -c serialib.cpp
g++ -c uart.cpp
g++ serialib.o uart.o -o uart
Or all in one command:
g++ serialib.cpp uart.cpp -o uart
You should read An Introduction to GCC to understand the commands, not just enter bogus commands without understanding them.
I have found a solution to this problem, hope this helps for all the future readers with similar problems. I have my own source code uart.cpp (Given in the question) which I want to compile, the external library is serialib that contains two main files (serialib.h and serialib.cpp), you will want to replace the following commands with respect to the files you have
Step 1: Compiling with position independent code
g++ -c -Wall -Werror -fpic serialib.cpp
Step 2: Creating a shared library
g++ -shared -o libserialib.so serialib.o , here the library is libserialib.so.
Step 3: Linking your source code with library
g++ -L /home/debian -lserialib uart.cpp -o uart
g++ -L /home/debian -Wall -o test uart.cpp -lserialib
You may save the library at a different path and you may have a different name of course. Suppose you have a library called libabc.so at the directory /home/user/myDir then the commands will be like:
g++ -L /home/user/myDir -labc your_code.cpp -o your_code
g++ -L /home/user/myDir -Wall -o test your_code.cpp -labc
test is out own program, lserialib is actually looking for libserialib.so and not serialib.o as gcc/g++ assumes all libraries start with lib and end with .so or .a and you can see the same goes for labc as it will look for libabc.so thus it is important to make sure your library name begins with lib and ends with .so or .a
Step 4: Making library available at run time
Here we provide the path where the library is actually stored, I saved it in the directory /home/debian which is why my command looks like:
export LD_LIBRARY_PATH=/home/debian:$LD_LIBRARY_PATH
if your library is saved at /path/to/file then the command will look like:
export LD_LIBRARY_PATH=/path/to/file:$LD_LIBRARY_PATH
This is to help the loader find the shared library and to view this path: echo $LD_LIBRARY_PATH and to unset this: unset LD_LIBRARY_PATH
To execute the program type either ./test or ./uart and in case of any modification to the main source code (uart.cpp in this case) , simply repeat step 3. I found the following link very useful: http://www.cprogramming.com/tutorial/shared-libraries-linux-gcc.html . Thank you to all of you who took time to read this question and especially those who gave me suggestions. If anyone has more or better solutions, feel free to post them here to assist future readers :).
Context: I am building some code for an embedded board. It calls for installing the Xilinx tools, the Linaro toolchain and then invoking a setup bash script in the development board build directory (let's call it setup.sh).
If I do not run setup.sh , I can then build one of the lower level libraries, which has it's own configure script (./configure) which calls the usual ./bootstrap script. In this scenario ./bootstrap , g++ in this case says it can find sstream (the C++ stream header). Ok. Fine.
When I run the setup.sh script (at the top level), g++ then says it CANNOT find sstream. So somehow the g++ environment is changed somehow, and it is this I am trying to figure out.
The output in this erroneous case is
g++ has streams in std:: namespace
g++ does not have sstream
g++ does not have strstream.h
g++ does not have strstrea.h
I am trying to debug this to find out what g++ thinks it is doing and why it cannot find the sstream header. What are some ways to look at what the g++ include and libstdc++ library paths are set to? What environment variables control the behavior of gcc/g++?
#
If I remember correctly, Xilinx ships their own gcc toolchain with their products.
Just add the -I compile file to point to the proper includes path.
Try to search for the header files inside Xilinx's /opt path, so you don't have a mismatch between the header version and the library version.
Makefile's usual env variables are:
# C Compiler: GNU C Compiler
CC = gcc
# Linker: GNU Linker
LD = ld
# C++ Compiler: GNU C++ Compiler
CPP = g++
Also check
CFLAGS
CPPFLAGS
LDFLAGS
Check if $CC is set after you execute setup.sh.
I want to set up LEDA library in my system.
I have downloaded LEDA library from the following link
http://www.algorithmic-solutions.info/free/d5.php
Instruction given in read me file
2. Preparations
---------------
Unpacking the LEDA distribution file
LEDA---.tar.gz will create the LEDA root
directory "LEDA---". You might want to rename
it or move it to some different place. Let denote the final
complete path name of the LEDA root directory.
To install and use the Unix object code of LEDA you have to modify
your environment as follows:
a) LEDAROOT:
Set the environment variable LEDAROOT to the LEDA root directory:
csh/tcsh: setenv LEDAROOT
sh/bash: LEDAROOT=
export LEDAROOT
b) Command Search Path:
Include $LEDAROOT/Manual/cmd into your command search path
(environment variable path (csh) or PATH (sh)) and call rehash (if
required by your system).
c) Shared Library: (for solaris, linux, irix, osf1)
If you planning to use shared libraries include $LEDAROOT into the
LD_LIBRARY_PATH search path. Then go to $LEDAROOT and type
make shared. This will construct the shared libraries from the static
libraries.
Please note: Building the shared library is not supported on each
platform.
d) xlman and demos: Go to $LEDAROOT and type make xlman to compile
and link LEDA's interactive manual reader xlman. Now you can start
xlman for reading and printing manual pages, starting demo programs
and browsing more release notes.
3. Compiling and linking application programs
---------------------------------------------
a) Use the -I compiler flag to tell the compiler where to find the
LEDA header files.
CC (g++) -I$LEDAROOT/incl -c file.c
b) Use the -L compiler flag to tell the compiler where to find the
library (libleda.a/so)
CC (g++) -L$LEDAROOT file.o -lleda -lX11 -lm
If using windows on solaris systems you might have to link
with the system socket library and the network services library as
well:
CC (g++) ... -lleda -lX11 -lsocket -lnsl -lm
c) Compile and link simultaneously with
CC (g++) -I$LEDAROOT/incl -L$LEDAROOT file.c -lleda -lX11 -lm
You may want to ask your system adminstrator to install the header
files and library in the system's default directories.
Then you no longer have to specify header and library search paths on
the compiler command line.
I followed these instruction but I got error in command
> make xlman
error
coredump#coredump-VPCCB15FG:~/Documents/LEDA$ make xlman
make -C demo/xlman
make: *** demo/xlman: No such file or directory. Stop.
make: *** [xlman] Error 2
someone please help me to setup library.
NOTE: For the free version of the Leda library, you don't have to build the package to use the library. It simply doesn't work.
To use the library simply include it in your compile line and linker.
If you are compiling from the shell (assuming you are using Linux), do the following:
1. Set the env variable to the library folder e.g export LEDAROOT= /path/to/Leda
2. Set the LD_LIBRARY_PATH env variable e.g export LD_LIBRARY_PATH=$LEDAROOT
Verify that this variables are set then you can compile and link and run. You can simply do
CC (g++) -I$LEDAROOT/incl -L$LEDAROOT file.c -lleda -lX11 -lm
With this you should be good to go.
If you are using an IDE, simply add the include path (i.e /path/to/leda) to you project settings.
This is all you have to do. Building the library does not work. Simply include it