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read

function read
Jump to headingread<TBuffer extends ArrayBufferView>(
fd: number,
buffer: TBuffer,
offset: number,
length: number,
position: ReadPosition | null,
callback: (
err: ErrnoException | null,
bytesRead: number,
buffer: TBuffer,
) => void
,
): void

Read data from the file specified by fd.

The callback is given the three arguments, (err, bytesRead, buffer).

If the file is not modified concurrently, the end-of-file is reached when the number of bytes read is zero.

If this method is invoked as its util.promisify() ed version, it returns a promise for an Object with bytesRead and buffer properties.

Type Parameters Jump to heading

Jump to headingTBuffer extends ArrayBufferView

Parameters Jump to heading

The buffer that the data will be written to.

Jump to headingoffset: number

The position in buffer to write the data to.

Jump to headinglength: number

The number of bytes to read.

Specifies where to begin reading from in the file. If position is null or -1 , data will be read from the current file position, and the file position will be updated. If position is an integer, the file position will be unchanged.

Jump to headingcallback: (
err: ErrnoException | null,
bytesRead: number,
buffer: TBuffer,
) => void

Return Type Jump to heading

void
Jump to headingread<TBuffer extends ArrayBufferView>(
fd: number,
options: ReadAsyncOptions<TBuffer>,
callback: (
err: ErrnoException | null,
bytesRead: number,
buffer: TBuffer,
) => void
,
): void

Similar to the above fs.read function, this version takes an optional options object. If not otherwise specified in an options object, buffer defaults to Buffer.alloc(16384), offset defaults to 0, length defaults to buffer.byteLength, - offset as of Node 17.6.0 position defaults to null

Type Parameters Jump to heading

Jump to headingTBuffer extends ArrayBufferView

Parameters Jump to heading

Jump to headingcallback: (
err: ErrnoException | null,
bytesRead: number,
buffer: TBuffer,
) => void

Return Type Jump to heading

void
Jump to headingread(
fd: number,
callback: (
err: ErrnoException | null,
bytesRead: number,
buffer: ArrayBufferView,
) => void
,
): void

Parameters Jump to heading

Jump to headingcallback: (
err: ErrnoException | null,
bytesRead: number,
buffer: ArrayBufferView,
) => void

Return Type Jump to heading

void
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