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Test if object is opened

is.open.rd

Test whether an ff or ffdf object or a ff_pointer is opened.

Usage

is.open(x, ...)
# S3 method for class 'ff'
is.open(x, ...)
# S3 method for class 'ffdf'
is.open(x, ...)
# S3 method for class 'ff_pointer'
is.open(x, ...)

Arguments

x

an ff or ffdf object

...

further arguments (not used)

Details

ff objects open automatically if accessed while closed. For ffdf objects we test all of their physical components including their row.names if they are is.ff

Value

TRUE or FALSE (or NA if not all components of an ffdf object are opened or closed)

Author

Jens Oehlschlägel

See also

is.readonly, open.ff, close.ff

Examples

  x <- ff(1:12)
  is.open(x)
#> [1] TRUE
  close(x)
#> [1] TRUE
  is.open(x)
#> [1] FALSE
  rm(x); gc()
#>           used (Mb) gc trigger  (Mb) max used  (Mb)
#> Ncells 1250121 66.8    2239654 119.7  2239654 119.7
#> Vcells 2301182 17.6    8388608  64.0  8387257  64.0