External Interfaces/API

Testing Your Configuration on UNIX

The quickest way to check if your system is set up properly to create MEX-files is by trying the actual process. There is C source code for an example, yprime.c, and its Fortran counterpart, yprimef.F and yprimefg.F, included in the <matlab>/extern/examples/mex directory, where <matlab> represents the top-level directory where MATLAB is installed on your system.

To compile and link the example source files, yprime.c or yprimef.F and yprimefg.F, on UNIX, you must first copy the file(s) to a local directory, and then change directory (cd) to that local directory.

At the MATLAB prompt, type

• mex yprime.c
  

This uses the system compiler to create the MEX-file called yprime with the appropriate extension for your system.

You can now call yprime as if it were an M-function.

• yprime(1,1:4)
  ans =
       2.0000   8.9685   4.0000    -1.0947
  

To try the Fortran version of the sample program with your Fortran compiler, at the MATLAB prompt, type

• mex yprimef.F yprimefg.F
  

In addition to running the mex script from the MATLAB prompt, you can also run the script from the system prompt.

Selecting a Compiler

To change your default compiler, you select a different options file. You can do this anytime by using the command

• mex -setup
  
       Using the 'mex -setup' command selects an options file that is
      placed in ~/matlab and used by default for 'mex'. An options
      file in the current working directory or specified on the
      command line overrides the default options file in ~/matlab.
  
      Options files control which compiler to use, the compiler and
      link command options, and the runtime libraries to link
      against.
  
      To override the default options file, use the 'mex -f' command
      (see 'mex -help' for more information).
  
  The options files available for mex are:
  
    1: <matlab>/bin/gccopts.sh :
           Template Options file for building gcc MEXfiles
  
    2: <matlab>/bin/mexopts.sh :
           Template Options file for building MEXfiles using the
            system ANSI compiler
  
  Enter the number of the options file to use as your default 
  options file:
  

Select the proper options file for your system by entering its number and pressing Return. If an options file doesn't exist in your MATLAB directory, the system displays a message stating that the options file is being copied to your user-specific matlab directory. If an options file already exists in your matlab directory, the system prompts you to overwrite it.

Note    The setup option creates a user-specific matlab directory in your individual home directory and copies the appropriate options file to the directory. (If the directory already exists, a new one is not created.) This matlab directory is used for your individual options files only; each user can have his or her own default options files (other MATLAB products may place options files in this directory). Do not confuse these user-specific matlab directories with the system matlab directory, where MATLAB is installed. To see the name of this directory on your machine, use the MATLAB command prefdir.

Using the setup option resets your default compiler so that the new compiler is used every time you use the mex script.

Building MEX-Files

Testing Your Configuration on Windows