installed compiler not found

I have installed the MinGW-w64 compiler but I still get an error message when trying to compile a cc file:

>> mex -setup c

MEX configured to use 'MinGW64 Compiler (C)' for C language compilation.

>> mex -setup c++

Error using mex

No supported compiler was found. You can install the freely available MinGW-w64 C/C++ compiler;

see Install MinGW-w64 Compiler. For more options, visit

https://www.mathworks.com/support/compilers.

>> mex 'keyInject_setFocus.cc'

Error using mex

No supported compiler was found. You can install the freely available MinGW-w64 C/C++ compiler;

see Install MinGW-w64 Compiler. For more options, visit

https://www.mathworks.com/support/compilers.

The same works fine on Matlab 2017b. Suggestions?

Answer 1

[Aghamarsh Varanasi]

Hi Raphael,

Firstly, make sure that you have installed the complete version of the MinGW compiler from the add-on section of MATLAB, as custom installations of MinGW compiler may not be compatible with MATLAB.

If this issues still persists and is only occurring after restarting MATLAB, here is a workaround.

[Raphael]

Hi Aghamarsh

I am not sure what you mean by complete vs. custom installation of the compiler. There was no such option in the Add-On Explorer. I simply clicked on Download and installed it

I ran mex -setpup -v as suggested in the workaround and got this:

.. Looking for compiler 'MinGW64 Compiler (C)' ...

... Looking for environment variable 'MW_MINGW64_LOC' ...Yes ('C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset').

... Looking for file 'C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset\bin\gcc.exe' ...Yes.

... Looking for folder 'C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset' ...Yes.

Found installed compiler 'MinGW64 Compiler (C)'.

Then I ran mex -setup C++ -v and got this

... Looking for compiler 'MinGW64 Compiler (C++)' ...

... Looking for environment variable 'MW_MINGW64_LOC' ...Yes ('C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset').

... Looking for file 'C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset\bin\g++.exe' ...Yes.

... Looking for folder 'C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset' ...Yes.

... Looking for environment variable 'MW_MINGW64_LOC' ...Yes ('C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset').

... Executing command 'C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset\bin\g++ -dumpmachine' ...No.

Did not find installed compiler 'MinGW64 Compiler (C++)'.

So the problem doesn't seem the environment variable but something else

[Aghamarsh Varanasi]

Hi Raphael,

I get that you have installed MinGW support package from the add-on section of MATLAB.

I suggest you to run these commands in the windows command prompt and give the outputs so that we can try to understand the root cause of the issue. Please ensure that the MinGW installation folder is added to the windows path.

1. g++ --version
2. g++ -dumpmachine
3. mex -setup cpp

[Raphael]

The MinGW installer folder was not added to the windows path and I can not add it manually (got a message error when I tried. Aslo, notcie that this location is hidden and the folder doesn't appear in the list when trying to add it to the path via the interface. But even when I did try to add it manually by writing the whole path I got an error message and could save the new path)

I also tried to run the command you suggested but got error messages:

C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset\bin\g++ --version

C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset\bin\g++ --version

↑

Error: Invalid use of operator.

>> C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset\bin\g++ -dumpmachine

C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset\bin\g++ -dumpmachine

↑

Error: Invalid use of operator.

>> mex -setup cpp

Error using mex

No supported compiler was found. You can install the freely available MinGW-w64 C/C++ compiler; see Install MinGW-w64 Compiler. For more options, visit

[Walter Roberson]

run the commands at the windows command prompt not the matlab command prompt.

Answer 2

[Raphael]

Oops. But now I am getting 'c:\ProgramData\...full_path ...\g++' is not recognized as an internal or external command, operable program or batch file

[Aghamarsh Varanasi]

Hi Raphael,

Make sure you have 'g++.exe' installed under "C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset\bin" folder. If you do not find 'g++.exe', I recommend you to uninstall and re-install the MinGW support package for MATLAB from the Add-Ons Manager.

[Raphael]

you can see from this screen shot that the files are indeed there

[Aghamarsh Varanasi]

Hi Raphael,

You can navigate to the folder that contains the MinGW installation and execute these commands in the "windows command prompt" and send back the output. This helps to get a understanding of the underlying issue.

Steps to execute the following commands :

1. Open Windows command prompt, by typing 'cmd' in the windows search bar. Click enter to open the windows command prompt.
2. Execute the command

> cd C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset\bin

to navigate to the MinGW installation folder

3. Execute the following commands

> .\g++.exe --version

> .\g++.exe -dumpmachine

4. Run the 'mex' setup command in the same location in the windows command prompt

> mex -setup cpp

Thanks

[Raphael]

Here is the output:

C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset\bin>.\g++.exe --version

g++.exe (x86_64-posix-seh-rev2, Built by MinGW-W64 project) 6.3.0

Copyright (C) 2016 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.

C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset\bin>.\g++.exe -dumpmachine

x86_64-w64-mingw32

C:\ProgramData\MATLAB\SupportPackages\R2020b\3P.instrset\mingw_w64.instrset\bin>mex -setup cpp

No supported compiler was found. You can install the freely available MinGW-w64 C/C++ compiler; visit https://www.mathworks.com/help/matlab/matlab_external/install-mingw-support-package.html. For more options, visit https://www.mathworks.com/support/compilers.

[Aghamarsh Varanasi]

Hi Raphael,

I understand that you have installed MinGW support package for MATLAB, but are not able to setup mex.

The outputs that you for the commands also suggest the same. As I am not able to reproduce the same at my end, I suggest you contact MathWorks support to resolve the issue.

www.mathworks.com/support/contact_us

Thanks