Creating MEX-Files

On this page…
Introduction MEX-Files on UNIX MEX-Files on Windows

Introduction

In addition to including fixedpoint.c and fixedpoint.h (see Structure of the S-Function), the sections that follow describe additional steps you need to take to create a MEX-file for your user-written fixed-point S-function.

Back to Top

MEX-Files on UNIX

On UNIX^® systems, to create a MEX-file for a user-written fixed-point S-function, you need to pass an extra argument, -lfixedpoint, to the mex command. For example,

mex('sfun_user_fxp_asr.c','-lfixedpoint')

Back to Top

MEX-Files on Windows

On Windows^® systems, to create a MEX-file for a user-written fixed-point S-function, you need to pass an extra argument to the mex command that identifies the appropriate version of libfixedpoint.lib. The version of libfixedpoint.lib that you use depends on the compiler that you specify when mex -setup is run. The possible versions, which are installed with Simulink software, are as follows:

• extern\lib\win32\lcc\libfixedpoint.lib

• extern\lib\win32\microsoft\libfixedpoint.lib

• extern\lib\win32\watcom\libfixedpoint.lib

For example, if Version 6.0 of the Microsoft^® Visual C++^® software is the compiler that the mex command is configured to use,

mex('sfun_user_fxp_asr.c',[matlabroot,'\extern\lib\win32\... 
microsoft\libfixedpoint.lib'])

If your C compiler is not listed, consider the following options:

• Use the LCC freeware compiler. LCC is normally installed when the MATLAB software is installed. When you run mex -setup on a Windows system, LCC should be listed as an option.

• Your compiler may provide tools for translating one of the libfixedpoint.lib files or extern/include/libfixedpoint.def to the required format.

Back to Top

Overflow Handling and Rounding Methods

Fixed-Point S-Function Examples

© 1984-2012- The MathWorks, Inc.    -   Site Help   -   Patents   -   Trademarks   -   Privacy Policy   -   Preventing Piracy   -   RSS