mxGetScalar (C and Fortran)

Real component of first data element in array

C Syntax

#include "matrix.h"
double mxGetScalar(const mxArray *pm);

Fortran Syntax

#include "fintrf.h"
real*8 mxGetScalar(pm)
mwPointer pm

Arguments

pm

Pointer to an mxArray; cannot be a cell mxArray, a structure mxArray, or an empty mxArray.

Returns

The value of the first real (nonimaginary) element of the mxArray.

In C, mxGetScalar returns a double. If real elements in the mxArray are of a type other than double, then mxGetScalar automatically converts the scalar value into a double. To preserve the original data representation of the scalar, cast the return value to the desired data type.

If pm points to a sparse mxArray, then mxGetScalar returns the value of the first nonzero real element in the mxArray. If there are no nonzero elements, then the function returns 0.

Description

Call mxGetScalar to get the value of the first real (nonimaginary) element of the mxArray.

Usually you call mxGetScalar when pm points to an mxArray containing only one element (a scalar). However, pm can point to an mxArray containing many elements. If pm points to an mxArray containing multiple elements, then the function returns the value of the first real element. For example, if pm points to a two-dimensional mxArray, then mxGetScalar returns the value of the (1,1) element. If pm points to a three-dimensional mxArray, then the function returns the value of the (1,1,1) element; and so on.

Use mxGetScalar on a nonempty mxArray of type numeric, logical, or char only. To test for these conditions, use Matrix Library functions such as mxIsEmpty, mxIsLogical, mxIsNumeric, or mxIsChar.

If the input value to mxGetScalar is type int64 or uint64, then the value might lose precision if it is greater than flintmax.

Examples

To open an example, type:

edit([fullfile(matlabroot,"extern","examples","refbook","filename")]);

where filename is:

To open an example, type:

edit([fullfile(matlabroot,"extern","examples","mex","filename")]);

where filename is:

To open an example, type:

edit([fullfile(matlabroot,"extern","examples","mx","filename")]);

where filename is: