Some string attributes are ``freeform'' and may contain any value without restrictions on format and length. Other string attributes are assumed to have a specific format. Still other string attributes must contain one of several well-known values. When this is the case, the well-known strings are padded with underscore characters to the length of the longest legal value.
Another type of string attribute is the ``pointer'' or ``variable'' attribute. These attributes take the form ``-->var-name''. A typical example is the image variable's ``image-max'' attribute, which in most MINC files contains the value ``-->image-max'', indicating that the image-max attribute value is stored in the variable of the same name.
Numeric attributes may be either integer or floating-point format. MINC includes attribute access routines which will automatically convert a value to the desired type on retrieval.