CDF_INQUIRE

The CDF_INQUIRE function returns global information about the Common Data Format file. This information is returned in a structure of the form:

{ NDIMS:0L, DECODING:"", ENCODING:"", MAJORITY:"", MAXREC:0L, $

  NVARS:0L, NZVARS:0L, NATTS:0L, DIM:LONARR(NDIMS) }

The tags of this structure are described below.

Calling Sequence

Result = CDF_INQUIRE( Id )

Arguments

Id

A CDF ID, returned from a previous call to CDF_OPEN or CDF_CREATE.

Explanation of the Structure Tags

NDIMS

The longword integer specifying the number of dimensions in the rVariables in the current CDF.

DECODING

A string describing the decoding type set in the CDF file. For example, 'MAC_DECODING' or 'ALPHAVMSD_ENCODING'.

ENCODING

A string describing the type of encoding used in the CDF file. For example, 'NETWORK_ENCODING' or 'SUN_ENCODING' .

MAJORITY

A string describing the majority used in the CDF file. The majority will be either row ( 'ROW_MAJOR' ) or column ( 'COL_MAJOR' ).

MAXREC

A longword integer specifying the highest record number written in the rVariables in the current CDF. The MAXREC field will contain the value -1 if no rVariables have yet been written to the CDF.

NVARS

A longword integer specifying the number of rVariables (regular variables) in the CDF.

NZVARS

A longword integer specifying the number of zVariables in the CDF.

NATTS

A longword integer specifying the number of attributes in the CDF. Note that the number returned in this field includes both global and variable attributes. You can use the GET_NUMATTR keyword to the CDF_CONTROL routine to determine the number of each.

DIM

A vector where each element contains the corresponding dimension size for the rVariables in the current CDF. For 0-dimensional CDF's, this argument contains a single element (a zero).

Example

cdfid = CDF_CREATE('CDFinquire', /HP_ENCODING, /MAC_DECODING)

attr1_id = CDF_ATTCREATE(cdfid, 'GLOBAL_ATT', /GLOBAL_SCOPE)

attr2_id = CDF_ATTCREATE(cdfid,'VARIABLE_ATT', /VARIABLE_SCOPE)

CDF_CONTROL, cdfid, GET_NUMATTRS = num_attrs

PRINT, 'This CDF has ', num_attrs(0), 'Global attribute(s) and ',$

    num_attrs(1), 'Variable attribute(s).', FORMAT='(A,I2,A,I2,A)'

IDL prints:

This CDF has 1 Global attribute(s) and 1 Variable attribute(s).

inquire = CDF_INQUIRE(cdfid)

HELP, inquire, /STRUCT

IDL prints:

** Structure <4003e0c0>, 9 tags, length=48, refs=1:

NDIMS LONG 0

DECODING STRING    'MAC_DECODING'

ENCODING STRING    'HP_ENCODING'

MAJORITY STRING    'ROW_MAJOR'

MAXREC LONG -1

NVARS LONG 0

NZVARS LONG 0

NATTS LONG 2

DIM LONG Array(1)

CDF_DELETE, cdfid ; Delete the CDF file.

See Also

CDF_CONTROL , CDF_DOC , CDF_LIB_INFO