How do I use Embedded Matlab Coder to generate C-code?

I am doing embedded C-Code generation using Embedded Matlab coder. I tried the Simulink Real-Time Workshop demo:

Demos>Simulink > Real-Time Workshop > Application Samples > Embeddable C-Code Generation Using Embedded MATLAB Coder

However after running:

emlc -T rtw:exe -o rtwdemo_emlcsobel rtwdemo_emlcmain.m stdio.h

I got the error:

??? Build error: Build failed for project "main_rtw". See the target build log for further details. Error in ==> main Line: 1 Column: 1 Compilation failed: Open error report.

I am using 32-bit Matlab R2008a on a Mac.

******* BUILD LOG ********

    1   gcc -c -O0   -DUSE_RTMODEL -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk -fno-common -no-cpp-precomp -fexceptions  -DMODEL=rtwdemo_emlcsobel -DRT -DNUMST=1 -DTID01EQ=0 -DNCSTATES=0 -DUNIX -DMT=0 -DHAVESTDIO  -I. -I/tmp/tp9376e37b_e846_409f_ba91_83b4281a6361/emlcdir -I/Applications/MATLAB_R2008a/simulink/include -I/Applications/MATLAB_R2008a/extern/include -I/tmp/tp9376e37b_e846_409f_ba91_83b4281a6361/emlcdir/emcprj/rtwexe/rtwdemo_emlcmain -I/tmp/tp9376e37b_e846_409f_ba91_83b4281a6361/emlcdir        main.c
    2   In file included from main.c:11:
    3   main.h:13:18: error: math.h: No such file or directory
    4   main.h:14:20: error: stdlib.h: No such file or directory
    5   main.h:15:20: error: string.h: No such file or directory
    6   In file included from /usr/llvm-gcc-4.2/bin/../lib/gcc/i686-apple-darwin11/4.2.1/include/limits.h:15,
    7                    from rtwtypes.h:21,
    8                    from main.h:18,
    9                    from main.c:11:
   10   /Developer/usr/llvm-gcc-4.2/lib/gcc/i686-apple-darwin11/4.2.1/include/limits.h:15:25: error: no include path in which to search for limits.h
   11   main.c:13:19: error: stdio.h: No such file or directory
   12   main.c: In function 'main':
   13   main.c:40: error: 'FILE' undeclared (first use in this function)
   14   main.c:40: error: (Each undeclared identifier is reported only once
   15   main.c:40: error: for each function it appears in.)
   16   main.c:40: error: 'eml_fid' undeclared (first use in this function)
   17   main.c:65: warning: incompatible implicit declaration of built-in function 'fwrite'
   18   main.c: In function 'm_refp1_sqrt':
   19   main.c:177: warning: incompatible implicit declaration of built-in function 'sqrt'
   20   gmake: *** [main.o] Error 1
   21

Could this be because I have XCode 4.0 installed? I check mex.getCompilerConfigurations() and it says it is using GNU g95. I am currently downloading XCode 3.0 to see if that helps.

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I tried running the same demo on a windows machine (64 bit R2010a) - I got a different error (do not have the error message) - it was something along the lines 'Could not locate MEX compiler options file mexopts.bat'. When I run mex -setup, it shows 0 compilers when I try to automatically locate a compiler. I have Visual Studio 2010 Express installed on this computer. I am currently downloading Visual Studio 2008 Express, because it looks like R2010a Simulink does not support 2010 Express (<http://www.mathworks.com/support/compilers/R2010a/win64.html)>.

Any help getting either of these issues sorted out would be appreciated.

Om

[Kaustubha Govind]

Please paste the target build log messages for the first case (the "Open error report" message should be a link that opens up the log). For the second case, make sure that you install a supported compiler and try again.

Answer 1

[Ryan Livingston]

If you have a look at the supported compilers for R2008a:

http://www.mathworks.com/support/compilers/release2008a/macintosh.html

you will notice that XCode is necessary for using Embedded MATLAB. If you run:

 mex -setup

in that MATLAB can you choose XCode as your compiler, does the code compile?

[Om]

I have XCode 4 installed and Matlab R2008a only supports XCode 3.0 so maybe that will solve the problem.

Answer 2

[Om]

Part 1 (Mac machine with R2008a): I noticed that XCode 4.0+ is not supported by Matlab R2008a, and I have XCode 4.4 installed on my computer. I don't want to install XCode 3.0, but I guess that could fix the problem. The emlc function is still generating C-code so it doesn't really matter at this point if Matlab is able to build it or not.

Answer to Part 2 (Windows machine with R2010a): By following http://www.mathworks.com/support/solutions/en/data/1-6IJJ3L/, I was able to use Visual Studio 2008 Express successfully with Matlab to compile mex files. In particular, I tried:

copyfile(fullfile(matlabroot,'extern','examples','mex',... 'yprime.c'), fullfile('c:','work')); Compile yprime.c.

mex yprime.c

and ran yprime(1,1:4) with the correct output.

However, when using the Embedded C-code Generator, Matlab would still fail to build. I have just given up - I don't actually need Matlab to build any of the generated C-code, since I can easily compile it outside of the Matlab environment. I just don't like seeing error messages when running a purchased toolbox.

[Kaustubha Govind]

Om: The issue seems to be that your compiler cannot find standard libraries. What if you modify yprime.c to include stdlib.h and attempt to use a function from that library? Does it still compile with the MEX command?