Intel 82854 GMCH, 82830M GMCH manual Icegdescapegetnumpdattributes Null

//(1)

int number;//available attributes number igd_attr_t *attr_list, *current;

/*other types such as igd_list_attr_t, igd_bool_attr_t, igd_string_attr_t can refer to the implement of igd_range_attr_t as below*/ igd_range_attr_t *range;

esc_status_t status;

ExtEscape(

Hdc,

ICEGD_ESCAPE_GET_NUM_PD_ATTRIBUTES, 0,

NULL,

sizeof(unsigned int), (LPSTR)&number);

//the attribute list should contain number entries of igd_attr_t. attr_list = (igd_attr_t *) calloc(number, sizeof(igd_attr_t));

//now the attr_list is the old configure of port driver ExtEscape(

Hdc,

ICEGD_ESCAPE_GET_AVAIL_PD_ATTRIBUTES, 0,

NULL,

number * sizeof(igd_attr_t), (LPSTR) attr_list);

current = attr_list;

for (int i=0; i<number; i++, current++)

{

//choose attribute DACA, and the type of it must be range

if (current->id == 26 && current->type == PD_ATTR_TYPE_RANGE)

{

/*to set the value must force the structure convert from igd_attr_t to igd_range_attr_t */

range = (igd_range_attr_t *) current;

//(2)

range->current_value = 2;

//(3)

memset(&status, 0, sizeof(esc_status_t));

ExtEscape(

Hdc,

ICEGD_ESCAPE_SET_PD_ATTRIBUTES, sizeof(igd_attr_t),

(LPCSTR) current, sizeof(esc_status_t), (LPSTR) &status);

break;

}

/*if type is list, there will follow some entries, the number of which is stored in the num_entries of the structure. So the pointer to the list should jump num_entries to find next attribute*/

if (current->type == PD_ATTR_TYPE_LIST) {

i+= ((igd_list_attr_t *)current)->num_entries; current += ((igd_list_attr_t *)current)->num_entries;

}

}

free(attr_list);

Intel® Digital Set Top Box Display Driver 33

User’s Guide for Microsoft* Windows* CE 5.0