Setting up MATLAB to compile m files to dll's for calling via C/C++ programs

Hi Everyone,

I'm new to the method of compiling m files to dll's so they can be called by C/C++ programs. I'm having general issues with setting up the Matlab compiler--I'm using Matlab 2011b. Specifically:

1. On the Matlab command line, mbuild -setup, shows a list of two compilers; lcc-win32 C 2.4.1 and Microscoft Visual C++ 2010. Is lcc-win32 C 2.4.1 the same as Matlab Compiler 4.16? The reason is that I plan to install Matlab Compiler Runtime (MCR) 7.16 and I read that the Matlab version and the compiler have to be compatible (Matlab R2011b uses compiler 4.16 and thus MCR 7.16).

2. Please let me know of any special set-up settings for the compiler. Currently, I'm using the command: mcc -t -W lib:LinearFitModelFn_lib -L C -T link:lib -h libmwsglm.mlib libmmfile.mlib LinearFitModelFn.m

I'm able to compile an m file to a c, h, dll, and lib file with the lcc compiler but I receive the following readout:

The -t switch is no longer supported; the Compiler no longer generates C/C++ source code for MATLAB functions (it generates wrapper functions instead, see the documenation for -W).

The -L switch is no longer supported; the target (-T) and wrapper (-W) switches determine the language of the generated code.

The -h switch is no longer supported; the MATLAB Compiler detects MATLAB file dependencies automatically. But see also the documentation for the -a switch. The -t switch is no longer supported; the Compiler no longer generates C/C++ source code for MATLAB functions (it generates wrapper functions instead, see the documenation for -W).

The -L switch is no longer supported; the target (-T) and wrapper (-W) switches determine the language of the generated code.

The -h switch is no longer supported; the MATLAB Compiler detects MATLAB file dependencies automatically. But see also the documentation for the -a switch.

The statement about C source code is no longer generated but rather wrapper code is a bit confusing as a c file is generated. Is this the c wrapped code? Anyway, before I ask more questions, I should first have the compiler issue corrected.

Thank you for your support; I appreciate any insight into the questions above.

Answer 1

[Walter Roberson]

MATLAB Compiler 4.16 is the R2011b version of the MATLAB Compiler software product, and MCR 7.16 is the MCR version associated with it.

The MATLAB Compiler product does not create C or C++ code: it creates an (encrypted) data file of threaded code (in its own internal languages) that MCR version knows how to execute at run-time.

It could be, though, that for internal purposes it needs a C compiler for an intermediate step, such as to generate appropriate machine code for a program to be able to use MCR as a DLL.

lcc is an older free C compiler that can be used to create mex files. Sometimes people run into problems because lcc is too old to know about some of the newer C constructs.

Use either compiler; it will not affect your DLL (not much anyhow.) On the other hand, the MS compiler might require that you include the MS runtime, maybe.

[KME]

Okay, thank you. After compiling my m file I opened the corresponding c and h files and noticed that they state in the metadata section "MATLAB Compiler: 4.16 (R2011b)". So Matlab compiler 4.16 must be the compiler? I then wrote a simple C/C++ console program in using VC 2010 which linked to the m file dll. I first installed MCR 7.16. The program crashes and upon debugging, the mxGetPr function returns a NULL pointer. My exact code referring to this is:

double myArray[5]={10.2, 3, 6.3, 5.4, 5.9};

double *myArrayPtr;

mxArray* t;

t=mxCreateDoubleMatrix(1, 5, mxREAL);

myArrayPtr = (double*)mxGetPr(t);

memcpy(myArrayPtr, myArray, 5*sizeof(double)); //Program Crashes here

I'm not sure if I'm using the MCR correctly. I just run the C/C++ program--am I missing a step? Could there be missing Matlab libraries for the mx functions--currently including mclmcrrt.lib.

Thanks for your help; I look forward to your response.

[KME]

I apologize, actually

t=mxCreateDoubleMatrix(1, 5, mxREAL);

is returning a NULL pointer.

[Walter Roberson]

The reference to 4.16 in the metadata is telling you which MATLB Compiler version generated the C code.

The -W (wrapper) that you referred to earlier are the same thing I was referring to about "appropriate machine code for a program to be able to use MCR as a DLL"

I do not have experience with writing MEX code.