MATLAB Shared Library

include ur c header files<br />
#include "mex.h"<br />
void timestwo(double y[], double x[])<br />
{<br />
y[0] = 2.0*x[0];<br />
}<br />
// This is the Gateway function<br />
void mexFunction(int nlhs, mxArray *plhs[], int nrhs,<br />
const mxArray *prhs[])<br />
{<br />
double *x, *y;<br />
int mrows, ncols;<br />
/* Check for proper number of arguments. */<br />
if (nrhs != 1) {<br />
mexErrMsgTxt("One input required.");<br />
} else if (nlhs > 1) {<br />
mexErrMsgTxt("Too many output arguments");<br />
}<br />
/* The input must be a noncomplex scalar double.*/<br />
mrows = mxGetM(prhs[0]);<br />
ncols = mxGetN(prhs[0]);<br />
if (!mxIsDouble(prhs[0]) || mxIsComplex(prhs[0]) ||<br />
!(mrows == 1 && ncols == 1)) {<br />
mexErrMsgTxt("Input must be a noncomplex scalar double.");<br />
}<br />
/* Create matrix for the return argument. */<br />
plhs[0] = mxCreateDoubleMatrix(mrows,ncols, mxREAL);<br />
/* Assign pointers to each input and output. */<br />
x = mxGetPr(prhs[0]);<br />
y = mxGetPr(plhs[0]);<br />
/* Call the timestwo subroutine. */<br />
timestwo(y,x);<br />
}<code><br />
<br />
save this code as a .c function(programname.c)<br />
go to the matlab command window<br />
if you are doing the mex function for the first time you have to do a mex setup<br />
<br />
the following are the steps to do that<br />
This example shows the process of setting your default compiler to the<br />
Microsoft Visual C++ Version 6.0 compiler.<br />
mex -setup(type in command window)<br />
Please choose your compiler for building external interface (MEX)<br />
files.<br />
Would you like mex to locate installed compilers [y]/n? n<br />
Select a compiler:<br />
[1] Compaq Visual Fortran version 6.6<br />
[2] Lcc C version 2.4<br />
[3] Microsoft Visual C/C++ version 6.0<br />
[0] None<br />
Compiler: 3<br />
Your machine has a Microsoft Visual C/C++ compiler located at<br />
D:\Applications\Microsoft Visual Studio. Do you want to use this<br />
compiler [y]/n? y<br />
Please verify your choices:<br />
Compiler: Microsoft Visual C/C++ 6.0<br />
Location: C:\Program Files\Microsoft Visual Studio<br />
Are these correct?([y]/n): y<br />
The default options file:<br />
"C:\WINNT\Profiles\username\ApplicationData\MathWorks\MATLAB\R13<br />
\mexopts.bat" is being updated from ...<br />
Building MEX-Files<br />
<br />
If the specified compiler cannot be located, you are given the message:<br />
The default location for compiler-name is directory-name,<br />
but that directory does not exist on this machine.<br />
Use directory-name anyway [y]/n?<br />
Using the setup option sets your default compiler so that the new compiler is<br />
used every time you use the mex script.<br />
<br />
Once you have chosen you compiler build ur program by typing<br />
mex programname.c<br />
then you can check your program by typing "programname(2)" in command window<br />
or you can create an m file to call this program<br />
%mfile<br />
x=2;<br />
y=programname(x);<br />
disp(y)<br />
%mfile ends<br />
<br />
check it out