If the attribute is an integer attribute,
this can be used to access the value.

If the attribute is a floating point attribute,
this can be used to access the value.

If the attribute is a date/time attribute,
this can be used to access the value.
time[0] contains the NX computational date
time[1] contains the NX computational time.

If the attribute is a string attribute, then
this is a pointer to the value. The maximum length
of this string is limited by UF_ATTR_MAX_STRING_LEN

If the attribute is a reference attribute, then
this is a pointer to the value. The value may
have an embedded expression with the following
syntax:
<Xm.n@exp_name> or <Xm,n@exp_name>
The X indicates that an expression is being
referenced. The m specifies the minimum field
width. If necessary, it is padded on the left to
make up the field width. The n specifies the
maximum number of digits after the decimal point of
the expression value. The decimal point can be
specified as either . or , thus either m.n or m,n
are acceptable.