MATLAB: MEX – xcodebuild: error: SDK “macosx10.15.4” cannot be located.

fortranmacmexmex compiler

I installed Xcode (11.4) and Intel Fortran Composer XE (19.1.0.166) on my machine (macOS Catalina 10.15.4) and since the macOS update, mex does not work anymore. I can run
mex -setup -v FORTRAN
which works and returns
Verbose mode is on.
... Looking for compiler 'Intel Fortran Composer XE' ...
... Looking for environment variable 'IFORT_COMPILER19' ...No.
... Looking for environment variable 'IFORT_COMPILER18' ...No.
... Looking for environment variable 'IFORT_COMPILER17' ...No.
... Looking for environment variable 'IFORT_COMPILER16' ...No.
... Looking for environment variable 'IFORT_COMPILER15' ...No.
... Executing command 'which ifort' ...Yes ('/usr/local/bin/ifort').
... Looking for folder '/opt/intel/compilers_and_libraries_2020.0.166/mac/bin/intel64' ...Yes.
... Looking for environment variable 'IFORT_COMPILER19' ...No.
... Looking for environment variable 'IFORT_COMPILER18' ...No.
... Looking for environment variable 'IFORT_COMPILER17' ...No.
... Looking for environment variable 'IFORT_COMPILER16' ...No.
... Looking for environment variable 'IFORT_COMPILER15' ...No.
... Executing command 'which ifort' ...Yes ('/usr/local/bin/ifort').
... Looking for folder '/opt/intel/compilers_and_libraries_2020.0.166/mac/compiler/lib' ...Yes.
... Executing command 'ifort --version | grep -Eo '[0-9]+\.[0-9]+\.[0-9]+' | head -1' ...Yes ('19.1.0').
... Executing command 'xcrun -sdk macosx --show-sdk-path' ...Yes ('/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk').
... Executing command 'defaults read com.apple.dt.Xcode IDEXcodeVersionForAgreedToGMLicense' ...No.
... Executing command 'defaults read /Library/Preferences/com.apple.dt.Xcode IDEXcodeVersionForAgreedToGMLicense' ...Yes ('11.4').
... Executing command '
agreed=11.4 
 if echo $agreed | grep -E '[\.\"]' >/dev/null; then 
 lhs=`expr "$agreed" : '\([0-9]*\)[\.].*'` 
  rhs=`expr "$agreed" : '[0-9]*[\.]\(.*\)$'` 
 if echo $rhs | grep -E '[\."]' >/dev/null; then 
 rhs=`expr "$rhs" : '\([0-9]*\)[\.].*'` 
 fi 
 if [ $lhs -gt 4 ] || ( [ $lhs -eq 4 ] && [ $rhs -ge 3 ] ); then 
 echo $agreed 
 else 
 exit 1
 fi 
 fi' ...Yes ('11.4').
... Executing command 'xcode-select -print-path' ...Yes ('/Applications/Xcode.app/Contents/Developer').
... Executing command 'find /Applications/Xcode.app/Contents/Developer -name libclang_rt.osx.a' ...Yes ('/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/11.0.3/lib/darwin/libclang_rt.osx.a').
... Looking for folder '/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/11.0.3/lib/darwin' ...Yes.
... Executing command 'which xcrun' ...Yes ('/usr/bin/xcrun').
... Looking for folder '/usr/bin' ...Yes.
... Executing command 'xcrun -sdk macosx --show-sdk-version' ...Yes ('10.15.4').
Found installed compiler 'Intel Fortran Composer XE'.
... Looking for compiler 'Intel Fortran Composer XE' ...
... Looking for environment variable 'IFORT_COMPILER19' ...No.
... Looking for environment variable 'IFORT_COMPILER18' ...No.
... Looking for environment variable 'IFORT_COMPILER17' ...No.
... Looking for environment variable 'IFORT_COMPILER16' ...No.
... Looking for environment variable 'IFORT_COMPILER15' ...No.
... Executing command 'which ifort' ...Yes ('/usr/local/bin/ifort').
... Looking for folder '/opt/intel/compilers_and_libraries_2020.0.166/mac/bin/intel64' ...Yes.
... Looking for environment variable 'IFORT_COMPILER19' ...No.
... Looking for environment variable 'IFORT_COMPILER18' ...No.
... Looking for environment variable 'IFORT_COMPILER17' ...No.
... Looking for environment variable 'IFORT_COMPILER16' ...No.
... Looking for environment variable 'IFORT_COMPILER15' ...No.
... Executing command 'which ifort' ...Yes ('/usr/local/bin/ifort').
... Looking for folder '/opt/intel/compilers_and_libraries_2020.0.166/mac/compiler/lib' ...Yes.
... Executing command 'ifort --version | grep -Eo '[0-9]+\.[0-9]+\.[0-9]+' | head -1' ...Yes ('19.1.0').
... Executing command 'xcrun -sdk macosx --show-sdk-path' ...Yes ('/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk').
... Executing command 'defaults read com.apple.dt.Xcode IDEXcodeVersionForAgreedToGMLicense' ...No.
... Executing command 'defaults read /Library/Preferences/com.apple.dt.Xcode IDEXcodeVersionForAgreedToGMLicense' ...Yes ('11.4').
... Executing command '
agreed=11.4 
 if echo $agreed | grep -E '[\.\"]' >/dev/null; then 
 lhs=`expr "$agreed" : '\([0-9]*\)[\.].*'` 
  rhs=`expr "$agreed" : '[0-9]*[\.]\(.*\)$'` 
 if echo $rhs | grep -E '[\."]' >/dev/null; then 
 rhs=`expr "$rhs" : '\([0-9]*\)[\.].*'` 
 fi 
 if [ $lhs -gt 4 ] || ( [ $lhs -eq 4 ] && [ $rhs -ge 3 ] ); then 
 echo $agreed 
 else 
 exit 1
 fi 
 fi' ...Yes ('11.4').
... Executing command 'xcode-select -print-path' ...Yes ('/Applications/Xcode.app/Contents/Developer').
... Executing command 'find /Applications/Xcode.app/Contents/Developer -name libclang_rt.osx.a' ...Yes ('/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/11.0.3/lib/darwin/libclang_rt.osx.a').
... Looking for folder '/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/11.0.3/lib/darwin' ...Yes.
... Executing command 'which xcrun' ...Yes ('/usr/bin/xcrun').
... Looking for folder '/usr/bin' ...Yes.
... Executing command 'xcrun -sdk macosx --show-sdk-version' ...Yes ('10.15.4').
Found installed compiler 'Intel Fortran Composer XE'.
MEX configured to use 'Intel Fortran Composer XE' for FORTRAN language compilation.
However, when I launch the compilation, I get the following error
Error using mex
xcodebuild: error: SDK "macosx10.15.4" cannot be located.
xcrun: error: sh -c '/Applications/Xcode.app/Contents/Developer/usr/bin/xcodebuild -sdk macosx10.15.4 -find clang 2> /dev/null' failed with
exit code 16384: (null) (errno=No such file or directory)
xcrun: error: unable to find utility "clang", not a developer tool or in PATH
Also, the command
xcode-select --print-path
returns as expected
/Applications/Xcode.app/Contents/Developer
I tried to switch the path to
sudo xcode-select --switch /Library/Developer/CommandLineTools
but I is even worse since I cannot even setup mex.
Does anyone have encounter a similar error? Thank you.

Best Answer

There seems to be some incompatibility for which I don't know where it comes from. Anyway, the way I got it to work with C/C++ is to
  1. backup (move out otherwise they are not updated properly) any mex_* definition files in /Users/<username>/Library/Application Support/MathWorks/MATLAB/<yourversion>
  2. go to /Applications/<yourmatlab.app>/bin/maci64/mexopts/
  3. edit both clang++_maci64.xml and clang_maci64.xml the following way:
from
        <SDKVER>
            <cmdReturns name="xcrun -sdk macosx --show-sdk-version"/>
        </SDKVER>
to 
        <SDKVER>
            <cmdReturns name="xcrun -sdk macosx --show-sdk-version | cut -c1-5"/>
        </SDKVER>
which actually changes 10.15.4 to 10.5 (and does something else apparently).
run 
mex -setup C++
mex -setup C
again.
Hth, cheers...
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