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Harris Geospatial / Docs Center / IDL Reference / I/O - HDF / HDF_DF24_LASTREF

HDF_DF24_LASTREF

HDF_DF24_LASTREF

The HDF_DF24_LASTREF function returns the reference number of the most recently read or written 24-bit image in an HDF file.

Examples


; Open an HDF file.
h=HDF_OPEN('myhdf.hdf') 
PRINT, HDF_DF24_LASTREF() 
; IDL prints 0, meaning that the call was successful, 
; but no reference number was available.
 
; Create a 3D array, representing a 24-bit image:
a = BINDGEN(3,100,100)   
 
; Write the 24-bit image to the file:
HDF_DF24_ADDIMAGE, 'myhdf.hdf', a
 
PRINT, HDF_DF24_LASTREF()
; IDL prints a reference number for the last operation 
; (for example, 2). Note the reference number is not 
; simply a 1-based "image number"; the reference number 
; could easily be "2" or "3", etc.
 
; Write another image to the file:
HDF_DF24_ADDIMAGE, 'myhdf.hdf', a   
 
; Print the last reference number:
PRINT, HDF_DF24_LASTREF()
PRINT, HDF_DF24_NIMAGES('myhdf.hdf')
; IDL prints "2" because we’ve written two images to the file.
; Close the file
HDF_CLOSE, h

Syntax


Result = HDF_DF24_LASTREF( )

Return Value


Returns the reference number of the most recently read or written image.

Arguments


None

Keywords


None

Version History


4.0

Introduced

See Also


HDF_DF24_ADDIMAGE, HDF_DF24_GETIMAGE, HDF_DF24_GETINFO, HDF_DF24_NIMAGES, HDF_DF24_READREF, HDF_DF24_RESTART, HDF_DFR8_LASTREF



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