instructions.md

Using C/MEX with MATLAB

1. You need a compiler.

• Supported compilers can be found here: MATLAB 2014b.
• I suggest the Microsoft Windows SDK 7.1, since that it what I used and included.
• I had some trouble installing the compiler, but the fix was to uninstall every Microsoft Redistributable Library 2010.

2. Using mex

• You can run mex from inside MATLAB or from a command line.
  • Example: mex exampleFunc.c
  • This will compile exampleFunc.c into a file called exampleFunc.mex which can be called as a function as exampleFunc
• You can always run help mex in MATLAB for more information such as how to specify output architecture, name, etc.

3. Example 1 - Return Values

• Returning an individual value.
  • mexErrMsgTxt - display an error
  • mxCreateNumericArray - have MATLAB create an array
  • mxGetData - get a pointer to the actual data from a MATLAB array
• Returning a list of values.
  • No new MATLAB functions.

4. Example 2 - Simple Processing

• Addition.
  • No new MATLAB functions.
• Low pass filter implemented as a singleton. (A class that can only be instantiated once)
  • mxCalloc - allocate memory
  • mexMakeMemoryPersistent - tell MATLAB not to auto clear certain memory
  • mxFree - free allocated memory
  • mexAtExit - tell MATLAB to call a function when clear functions is run

5. Example 3 - Class

• Low pass filter implemented as a class that can be instantiated many times.
  • mxIsStruct - test if array is a struct array
  • mxGetField - get a field from a struct array
  • mxSetField - set a field from in a struct array
  • mxCreateStructArray - have MATLAB create a struct array
  • mxIsDouble - test if array is a double array
  • mxGetNumberOfElements - get the length of an array
  • mxCreateDoubleMatrix - have MATLAB create a double array

6. Example 4 - Windows API

• Beep.
  • Windows API
    • Beep - make a beep from the motherboard speaker at a frequency for a duration
• Window list.
  • Windows API
    • EnumWindows - list all of the windows on the system
    • GetWindowText - get the window title for a specific window
    • GetWindowLong - get properties about the window
  • MATLAB API
    • mxCreateStructMatrix - have MATLAB create a struct array