Why char is stored as 2 bytes in S-Function?

Hi all,

I would like to pass an uint8 array to my S-Function as a parameter:

inParam = char(uint8(1:7))

In the S-Function I did the followings

UINT8_T *inParam = (UINT8_T *)mxGetPr(ssGetSFcnParam(S, PARAM_IN_PORT_NR)); //;

but I saw that atually the array elements are stored as 2 bytes.

UINT16_T *inPorts = (UINT16_T *)mxGetPr(ssGetSFcnParam(S, PARAM_IN_PORT_NR)); //
// I can loop through the data
// This is only a snipet
*(inPorts++);

Why is that? Is this happening in all the Matlab versions?