选择指定图层上的所有实体

Acad::ErrorStatus selectEntityInLayer(const char* nLayerName,AcDbObjectIdArray& nIDs)
{
 Acad::ErrorStatus es = Acad::eOk;

 ads_name ents;
 struct resbuf *rb;
 rb=acutNewRb(AcDb::kDxfLayerName);
 rb->restype=8;
 rb->resval.rstring=(char*)nLayerName;
 rb->rbnext=NULL;
 acedSSGet("X",NULL,NULL,rb,ents);
 long entNums=0;
 acedSSLength(ents,&entNums);
 if (entNums == 0)
  es = Acad::eInvalidInput;
 else
 {
  for (long a = 0; a < entNums ; a ++)
  {
   AcDbObjectId  objId;
   ads_name      ent;
   acedSSName(ents,a,ent);
   acdbGetObjectId(objId, ent);
   nIDs.append(objId);
  }
 }
 acedSSFree(ents);
 acutRelRb(rb);

 return es;
}