The CDF_OPEN function opens an existing Common Data Format file.
id = CDF_OPEN('open_close.cdf')
Result = CDF_OPEN(Filename [, /READONLY] )
If successful, the CDF ID for the file is returned.
A scalar string containing the name of the file to be created. Note that if the desired filename has a .cdf ending, you can omit the extension and specify just the first part of the filename. For example, specifying “mydata” would open the file mydata.cdf.
Set this keyword to open the specified CDF file in readonly mode. Opening a file in readonly mode will result in significant performance improvement if there is a large amount of metadata and a large portion of the metadata is read.
READONLY keyword added