Test if object is opened

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

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

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 1160015 62.0    1994352 106.6  1994352 106.6
#> Vcells 2160923 16.5    8790397  67.1  8790397  67.1