# eio_fallocate

(PECL eio >= 0.0.1dev)

eio_fallocate — Allows the caller to directly manipulate the allocated disk space for a file

### Description

eio_fallocate ( mixed `$fd` , int `$mode` , int `$offset` , int `$length` [, int `$pri` = EIO_PRI_DEFAULT [, callable `$callback` = NULL [, mixed `$data` = NULL ]]] ) : resource

eio_fallocate() allows the caller to directly manipulate the allocated disk space for the file specified by `fd` file descriptor for the byte range starting at `offset` and continuing for `length` bytes.

> Note: File should be opened for writing

> `EIO_O_CREAT` should be logically OR'd with `EIO_O_WRONLY`, or `EIO_O_RDWR`

### Parameters

`fd`

  Stream, Socket resource, or numeric file descriptor, e.g. returned by eio_open().

`mode`

  Currently only one flag is supported for mode: `EIO_FALLOC_FL_KEEP_SIZE` (the same as POSIX constant `FALLOC_FL_KEEP_SIZE`).

`offset`

  Specifies start of the byte range.

`length`

  Specifies length the byte range.

`pri`

  The request priority: `EIO_PRI_DEFAULT`, `EIO_PRI_MIN`, `EIO_PRI_MAX`, or `NULL`. If `NULL` passed, `pri` internally is set to `EIO_PRI_DEFAULT`.

`callback`

  `callback` function is called when the request is done. It should match the following prototype:

  `void callback(mixed $data, int $result[, resource $req]);`
  `data`

    is custom data passed to the request.

  `result`

    request-specific result value; basically, the value returned by corresponding system call.

  `req`

    is optional request resource which can be used with functions like eio_get_last_error()

`data`

  Arbitrary variable passed to `callback`.

### Return Values

eio_fallocate() returns request resource on success or `FALSE` on error.