class

IO::MultiWriter

An IO which writes to a number of underlying writer IOs.

io1 = IO::Memory.new
io2 = IO::Memory.new
writer = IO::MultiWriter.new(io1, io2)
writer.puts "foo bar"
io1.to_s # => "foo bar\n"
io2.to_s # => "foo bar\n"

Constructors

new(writers : Array(IO), sync_close : Bool = false)

Creates a new IO::MultiWriter which writes to writers. If sync_close is set, calling #close calls #close on all underlying writers.

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new(*writers : IO, sync_close : Bool = false)

Creates a new IO::MultiWriter which writes to writers. If sync_close is set, calling #close calls #close on all underlying writers.

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Instance methods

Closes this IO.

IO defines this is a no-op method, but including types may override.

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closed?

Returns true if this IO is closed.

IO defines returns false, but including types may override.

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flush

Flushes buffered data, if any.

IO defines this is a no-op method, but including types may override.

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read(slice : Bytes) : NoReturn

Reads at most slice.size bytes from this IO into slice. Returns the number of bytes read, which is 0 if and only if there is no more data to read (so checking for 0 is the way to detect end of file).

io = IO::Memory.new "hello"
slice = Bytes.new(4)
io.read(slice) # => 4
slice          # => Bytes[104, 101, 108, 108]
io.read(slice) # => 1
slice          # => Bytes[111, 101, 108, 108]
io.read(slice) # => 0

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sync_close=(sync_close : Bool)

If #sync_close? is true, closing this IO will close all of the underlying IOs.

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sync_close?

If #sync_close? is true, closing this IO will close all of the underlying IOs.

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write(slice : Bytes) : Nil

Writes the contents of slice into this IO.

io = IO::Memory.new
slice = Bytes.new(4) { |i| ('a'.ord + i).to_u8 }
io.write(slice)
io.to_s # => "abcd"

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