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isopen

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.

Examples

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

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

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

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

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

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

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

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

julia> isopen(file)
false

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

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