typedef struct			// group A* struct
{
short f[5000];			// it was var but short works better -> and works with as high as 5000 elements too!!!
short g[5000];			// it was var but short works better
short h[5000];			// it was var but short works better
short parent_cluster[5000];
char clist[5000];		// BOOL 
char olist[5000];		// BOOL 
} PLAY02_CLUSTERASTARSYS;

PLAY02_CLUSTERASTARSYS* play02_group_astar = NULL;

...

play02_group_astar = (PLAY02_CLUSTERASTARSYS*)sys_malloc( (int)m * sizeof(PLAY02_CLUSTERASTARSYS) );	
memset( play02_group_astar , 0 , (int)m*sizeof(PLAY02_CLUSTERASTARSYS) );

function foo()
{
  SPOT* myspot = malloc(sizeof(SPOT)); // creates a new SPOT struct at runtime
  memset(myspot,0,sizeof(SPOT)); // set the struct content to zero (it's undefined after malloc)
  myspot->x = 1;  
  SPOT* spot_array = malloc(100*sizeof(SPOT)); // creates an array of 100 SPOT structs
  memcpy(&spot_array[0],myspot,sizeof(SPOT));  // copy the myspot struct to the first member of the array
  ...
  free(myspot); // removes the created structs
  free(myspot_array);
}