MEX cannot find a supported compiler in MATLAB R2015b after I upgraded to Xcode 8.0

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I installed Xcode 8.0 on my Mac and tried to use MEX. But I received the following error at the MATLAB command prompt. Please help, thanks.
>> mex -setup
Error using mex
No supported compiler or SDK was found. For options, visit

Accepted Answer

Walter Roberson
Walter Roberson on 18 Sep 2016
Go to the folder /Applications/ and edit the files clang++_maci64.xml and clang_maci64.xml . In both of those files, search for lines containing the string MacOSX10.10.sdk or MacOSX10.11.sdk . Duplicate the line and change it to MacOSX10.12.sdk . You will need to change 4 lines total in each of the two files, a line that mentions dirExists then a line that mentions cmdReturns and then the same two again.
Now, go into either Applications or LaunchPad and find your XCode icon, and launch it. You will need to agree to the license terms. If XCode launches without presenting the license terms dialog then you have already agreed for that version and do not need to repeat it.
The edits and the license agreement having been done, you should now be able to go into MATLAB and use
mex -setup C
mex -setup C++
Pierre on 1 Dec 2022 at 21:55
Works also for later versions of XCode (10) and MacOSX (Mojave).
Thanks a million.

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More Answers (4)

Karthikeyan Chandrasekaran
I followed the above steps.I could see MacOSX10.12.sdk already there. but still i am not able to figure out the problem
OS:MACOS i am using Xcode_beta,MATLAB2016b..
>> mex -setup C Warning: Xcode is installed, but its license has not been accepted. Run Xcode and accept its license agreement.
Error using mex No supported compiler or SDK was found.
Can anyone please help me regarding this where i am going wrong ?
  1 Comment
Walter Roberson
Walter Roberson on 7 Nov 2016
Go into Launcher, click on XCode. Or find it in Applications and double-click it. When it starts up it will ask you to confirm that you accept the license. Once you accept it, mex will work.

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changxun fan
changxun fan on 26 Feb 2017
it's work! thank so much.

xu tiantian
xu tiantian on 19 Aug 2018
Walter Roberson's answers have solved my problems perfectly. Thanks so much.

Melanie Renn
Melanie Renn on 23 Jul 2020
Edited: Melanie Renn on 23 Jul 2020
I installed Xcode 11.3.1 on my Mac (OS Catalina 10.15.5) and tried to use MEX. I followed Walter's steps above, but I am still getting the following error:
Error using mex
No supported compiler was found. For options, visit
Please help. Thanks in advance.


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