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(PECL eio >= 0.0.1dev)
eio_read — Read from a file descriptor at given offset
$fd
,$length
,$offset
,$pri
,$callback
,$data
= NULL
eio_read() reads up to length
bytes from fd
file descriptor at
offset
. The read bytes are stored in
result
argument of callback
.
fd
Stream, Socket resource, or numeric file descriptor
length
Maximum number of bytes to read.
offset
Offset within the file.
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
.
eio_read() stores read bytes in
result
argument of callback
function.
Example #1 eio_read() example
<?php
// Open a temporary file and write some bytes there
$temp_filename = "eio-temp-file.tmp";
$fp = fopen($temp_filename, "w");
fwrite($fp, "1234567890");
fclose($fp);
/* Is called when eio_read() is done */
function my_read_cb($data, $result) {
global $temp_filename;
// Output read bytes
var_dump($result);
// Close file
eio_close($data);
eio_event_loop();
// Remove temporary file
@unlink($temp_filename);
}
/* Is called when eio_open() is done */
function my_file_opened_callback($data, $result) {
// $result should contain the file descriptor
if ($result > 0) {
// Read 5 bytes starting from third
eio_read($result, 5, 2, EIO_PRI_DEFAULT, "my_read_cb", $result);
eio_event_loop();
} else {
// eio_open() failed
unlink($data);
}
}
// Open the file for reading and writing
eio_open($temp_filename, EIO_O_RDWR, NULL,
EIO_PRI_DEFAULT, "my_file_opened_callback", $temp_filename);
eio_event_loop();
?>
The above example will output something similar to:
string(5) "34567"