eio_polleio_read
(PECL eio >= 0.0.1dev)
eio_read — Read from a file descriptor at given offset.
Descrição
eio_read() reads up to length bytes from fd file descriptor at offset. The read bytes are stored in result argument of callback.
Parâmetros
- fd
-
The 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:
$data is custom data passed to the request. $result contains request-specific result value; basically, the value returned by corresponding system call.void callback($data, $result); - data
-
Arbitrary variable passed to callback.
Valor Retornado
eio_read() stores read bytes in result argument of callback function.
Exemplos
Exemplo #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();
?>
O exemplo acima irá imprimir algo similar a:
string(5) "34567"
Veja Também
- eio_open
- eio_write
- eio_close
- eio_event_loop
eio_read