isopen(object) -> Bool

Determine whether an object - such as a stream, timer, or mmap -- is not yet closed. Once an object is closed, it will never produce a new event. However, a closed stream may still have data to read in its buffer, use eof to check for the ability to read data. Use poll_fd to be notified when a stream might be writable or readable.


julia> file = open("data.txt", "r");
julia> isopen(file)

In this example, isopen is used to check if the file object file is open.

julia> sock = connect("localhost", 8080);
julia> isopen(sock)

Here, isopen is used to check if the socket connection sock is open.

julia> timer = Timer(1000);
julia> isopen(timer)

This example demonstrates checking if a timer object timer is open using isopen.

julia> memmap = Mmap.mmap("file.bin");
julia> isopen(memmap)

In this case, isopen is used to check if the memory-mapped file memmap is open.

julia> isopen(file)

After closing the file object file, isopen returns false to indicate that it is no longer open.

Note: It is important to check if an object is open before performing any operations on it to avoid potential errors.

See Also

deserialize, eachline, eof, fd, flush, IOBuffer, ismarked, isopen, isreadonly, mark, nb_available, open, pipeline, position, read, read!, readavailable, readbytes, readbytes!, readline, redirect_stderr, redirect_stdin, reset, seek, seekend, seekstart, serialize, skip, skipchars, TextDisplay, unmark, write, writemime,

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