CDF_ATTGET_ENTRY

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The CDF_ATTGET_ENTRY procedure reads a variable attribute's entry 
from a CDF file. 

Syntax 
CDF_ATTGET_ENTRY, Id, Attribute, EntryNum, Value, AttributeEntryType, 
            Value, Status  
            [,CDF_TYPE= attribute_entry_datatype] 
            [, ATTRIBUTE_NAME=attribute_name] 
            [,/ZVARIABLE] 

Arguments 
---------
Id 
The CDF ID, returned from a previous call to CDF_OPEN or CDF_CREATE. 

Attribute 
A string containing the name of the attribute or the attribute number 
from which attribute entry is retrieved. 

EntryNum 
The entry number. If the attribute is variable in scope, this is either the 
name or number of the variable the attribute is to be associated with. If 
the attribute is global in scope, this is the actual gEntry. It is the 
user's responsibility to keep track of valid gEntry numbers. Normally, 
gEntry numbers will begin with 0 or 1 and will increase up to MAXGENTRY (as 
reported in the GET_ATTR_INFO structure returned by CDF_CONTROL), but this 
is not required. 

AttributeEntryType 
The data type of the requested attribute entry

Value 
A named variable in which the value of the attribute is returned. 

Status 
Return status.  1 is returned if the requested attribute exist and its 
entry is retrieved. Otherwise, 0 is returned.


Keywords 
--------
CDF_TYPE 
Set this keyword equal to a named variable that will contain the CDF type of
the attribute entry, returned as a scalar string. Possible returned values 
are: CDF_CHAR, CDF_UCHAR, CDF_INT1, CDF_BYTE, CDF_UINT1, CDF_UINT2, 
CDF_INT2, CDF_UINT4, CDF_INT4, CDF_REAL4, CDF_FLOAT, CDF_REAL8, 
CDF_DOUBLE, CDF_EPOCH, or CDF_EPOCH16. If the type cannot be determined, 
"UNKNOWN" is returned. 


ATTRIBUTE_NAME
The name of the requested attribute number.


ZVARIABLE 
If EntryNum is a variable ID (as opposed to a variable name) and the variable
is a zVariable, set this flag to indicate that the variable ID is a zVariable
ID. The default is to assume that EntryNum is an rVariable ID. 

Note: the attribute must have a scope of VARIABLE_SCOPE. 

Examples
-------- 
id   = cdf_open('test.cdf')
inq  = cdf_inquire(id)

; Read all the variable attribute entries.

for var_num = 0, inq.nzvars-1 do begin
    for attr_num = 0, inq.natts-1 do begin
        cdf_attget_entry, id, attr_num, var_num, att_type, value, 
               status, /zvar, cdf_type=cdf_type, attribute_name=att_name
        if status ne 1 then continue
        print, "attr_name = ", att_name, ", ", cdf_type, ", ", value
    endfor
endfor