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isOpen -- whether a file or database is open

Usage:

isOpen f
Inputs:
- f, a file or a database
Outputs:
- a Boolean value, whether f is an open file or open database

Description

An open file is either an input file, an output file, an input output file, or a listener.

i1 : f = "test-file" << "hi there"

o1 = test-file

o1 : File

i2 : isOpen f

o2 = true

i3 : close f

o3 = test-file

o3 : File

i4 : isOpen f

o4 = false

i5 : get "test-file"

o5 = hi there

i6 : removeFile "test-file"

See also

openIn -- open an input file
openInOut -- open an input output file
openListener -- open a port for listening
close -- close a file
get -- get the contents of a file
removeFile -- remove a file

Ways to use isOpen:

isOpen(Database)
isOpen(File)

For the programmer

The object isOpen is a compiled function.

The source of this document is in Macaulay2Doc/ov_system.m2:611:0.