MATLAB: Does MATLAB Coder locate the wrong toolchain when trying to build code for a specific hardware on the Linux machine (MATLAB R2017b)

matlab coder

I am currently running MATLAB on a linux system with centos 7.2 server and have gcc 4.8.5 installed as the default compiler on my machine (which is confirmed by executing "gcc -v"). I have also selected gcc 4.8.5 in MATLAB through the "mex -setup" command, however, when I try to automatically locate an installed toolchain in MATLAB Coder for the build process on a specified hardware board, "GNU gcc/g++ v4.4x" gets chosen instead of gcc v4.8. I am even unable to find v4.8 in the drop-down list and in the Target Build Log, GNU gcc/g++ v4.4.x shows up.

How do I use gcc v4.8.5 with MATLAB Coder even though it is selected as the compiler in MATLAB?

Best Answer

The toolchain name that appears in MATLAB Coder (GNU gcc/g++ v4.4.x) is misleading. Even though the toolchain states gcc v4.4, the compiler being used is actually the one that is set up through "mex -setup", which in your case is v4.8.5.

Related Solutions

MATLAB: How to change the current GCC/G++ version to a supported one

Currently it is not possible to select a supported compiler with "mex -setup" in LINUX and MAC based systems.

As a workaround, please consider using any of the following:

A. Make system's default "gcc" command point to the supported GCC version

   1. Open the terminal window in LINUX and execute the command:
          $ which gcc
      This will provide the symbolic link (softlink) to the default version of GCC.
   2. Navigate to the directory which has this softlink.
      Change the softlink to point to the version of GCC that you want to use.
      For example, for a standard GCC version 4.7 installed (where the compiler command is put at /usr/bin/gcc-4.7),
      this can be done using the following command:
          $ sudo ln -f -s /usr/bin/gcc-4.7 gcc
      Here "gcc" is the name of the softlink determined in step 1.
      If you execute the command “ls –l gcc” on the terminal, it will indicate that softlink points to gcc-4.7.
      Note: As an alternative to steps 1 and 2 above, you should also be able to use the following one liner:
          $ sudo ln -s -f `dirname \`which gcc\``/gcc-4.3 `which gcc`
   3. Now open MATLAB and execute the following command:
          >> !gcc --version
      This command reflects the version of GCC compiler that is currently being used by MATLAB.
      If you specify gcc-4.7 as above, it will indicate “gcc-4.7”.
      You may also use the verbose mode ("-v" flag) to display detailed build information:
          >> mex -v timestwo.c

B. (For MATLAB releases R2013b and before) Specify the supported GCC compiler in the "mexopts.sh"

   On MATLAB command window, first execute "mex -setup" and then select "1" and finally "y"
   which will include output similar to:
       /usr/local/MATLAB/R2013b/bin/mexopts.sh is being copied to 
       /home/<username>/.matlab/R2013b/mexopts.sh
   Open "/home/<username>/.matlab/R2013b/mexopts.sh' with an editor. The compiler is specified with CC='gcc'.
   Replace the 'gcc' part with the path of the supported compiler as in:
       CC='/usr/bin/gcc-4.7'

C. Specify the compiler while using the "mex" command (this overrides the default compiler)

   <For MATLAB releases R2014a and after>
   Specify the path of the supported compiler in the compiler option (CC or GCC):
          >> mex -v GCC='/usr/bin/gcc-4.7' timestwo.c
          >> mex -v CC='/usr/bin/gcc-4.7' timestwo.c
   <For MATLAB releases R2013b and before>
   Specify the path of the supported compiler in the compiler option (CC):
         >> mex -v CC='/usr/bin/gcc-4.7' timestwo.c

MATLAB: How to modify the build information for mex code generation with the codegen function

Codegen('mex') does not support custom toolchains, as noted in the documentation at the following link:

https://www.mathworks.com/help/coder/ug/use-the-custom-toolchain.html

Compiler settings are inherited from the "mex -setup" command.

Instead, you can use the Post-Code-generation command to pass a custom Build Information Object to the "codegen" command.

For example, you could add a link flag with the following function:

function setbuildargs(buildInfo)
     linkFlags = {'-lpthread'};
     buildInfo.addLinkFlags(linkFlags);
     cfg = coder.config('mex');
end

That function can then be used to pass the build information object via the PostCodeGenCommand:

>> cfg.PostCodeGenCommand = 'setbuildargs(buildInfo)';

More information and further examples can be found in the documentation at the following link:

https://www.mathworks.com/help/coder/ug/customizing-the-post-code-generation-build-process.html

Best Answer

Related Solutions

MATLAB: How to change the current GCC/G++ version to a supported one

MATLAB: How to modify the build information for mex code generation with the codegen function

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