User`s manual

C MEX-Files
2-5
Required Arguments to a MEX-File
The two components of the MEX-file may be separate or combined. In either
case, the files must contain the
#include "mex.h" header so that the entry
point and interface routines are declared properly. The name of the gateway
routine must always be
mexFunction and must contain these parameters.
void mexFunction(
int nlhs, mxArray *plhs[],
int nrhs, const mxArray *prhs[])
{
/* more C code ... */
The parameters nlhs and nrhs contain the number of left- and right-hand
arguments with which the MEX-file is invoked. In the syntax of the MATLAB
language, functions have the general form
[a,b,c,…] = fun(d,e,f,…)
where the ellipsis (…) denotes additional terms of the same format. The a,b,c,…
are left-hand arguments and the
d,e,f,… are right-hand arguments.
The parameters
plhs and prhs are vectors that contain pointers to the left- and
right-hand arguments of the MEX-file. Note that both are declared as
containing type
mxArray *, which means that the variables pointed at are
MATLAB arrays.
prhs is a length nrhs array of pointers to the right-hand side
inputs to the MEX-file, and
plhs is a length nlhs array that will contain
pointers to the left-hand side outputs that your function generates.