MATLAB: Using MEX file and constants

Question

Hello,

I need to use PI value inside the mex file. how should i do it? (because right now I'm getting an error): Error GMSK_viterbi.c: 66 undeclared identifier `PI'

Answer 1

One way:

#include <math.h>

Then use M_PI for the value in your code instead of PI, or you could add this line also:

#define  PI  M_PI

Another way:

#define  PI  3.1415926535897932

One could also use compile option -D to get it defined.