get_resource_type

(PHP 4 >= 4.0.2, PHP 5, PHP 7)

get_resource_type — 返回资源（resource）类型

描述

get_resource_type ( resource $handle ) : string

此函数返回一个字符串，用于表示传递给它的 resource 的类型。如果参数不是合法的 resource，将产生错误。

<?php
$c = mysql_connect();
echo get_resource_type($c)."\n";
// 打印：mysql link

$fp = fopen("foo","w");
echo get_resource_type($fp)."\n";
// 打印：file

$doc = new_xmldoc("1.0");
echo get_resource_type($doc->doc)."\n";
// 打印：domxml document
?>

User Contributed Notes

CertaiN 17-Jan-2014 05:04
Try this to know behavior:

<?php
function resource_test($resource, $name) {
    echo
        '[' . $name. ']',
        PHP_EOL,
        '(bool)$resource => ',
        $resource ? 'TRUE' : 'FALSE',
        PHP_EOL,
        'get_resource_type($resource) => ',
        get_resource_type($resource) ?: 'FALSE',
        PHP_EOL,
        'is_resoruce($resource) => ',
        is_resource($resource) ? 'TRUE' : 'FALSE',
        PHP_EOL,
        PHP_EOL
    ;
}
 
$resource = tmpfile();
resource_test($resource, 'Check Valid Resource');
 
fclose($resource);
resource_test($resource, 'Check Released Resource');
 
$resource = null;
resource_test($resource, 'Check NULL');
?>

It will be shown as...

[Check Valid Resource]
(bool)$resource => TRUE
get_resource_type($resource) => stream
is_resoruce($resource) => TRUE

[Check Released Resource]
(bool)$resource => TRUE
get_resource_type($resource) => Unknown
is_resoruce($resource) => FALSE

[Check NULL]
(bool)$resource => FALSE
get_resource_type($resource) => FALSE
Warning:  get_resource_type() expects parameter 1 to be resource, null given in ... on line 10
is_resoruce($resource) => FALSE
avp200681 at gmail dot com 13-Jun-2011 03:11
This function will generate an error and return NULL instead FALSE in the next example:

<?php

$var = 3;
var_dump(get_resource_type($var));

?>
hessodreamy at gmail dot com 29-May-2007 04:07
Furthermore, this function returns 'stream' on php 4.3 on windows & linux.
You if you want to differentiate between a file resource and other stream resources, as stated before stream_get_meta_data() gives you an array which, on my system, contains the following elements which might suggest a file handle:
[wrapper_type] => plainfile
[stream_type] => STDIO

However I've only compared this to a stream from a url, so I include this only as a suggestion.
jdhawk _at_ gmail 05-Oct-2005 01:18
In PHP5 (on Linux), the above example identifies the "file" handler as a 'stream', not 'file'.

This can be particularly worrisome if you're trying to determine the type of stream using this function.

The alternative is to use <?php stream_get_meta_data() ?>, which returns an array containing "stream_type (string) - a label describing the underlying implementation of the stream."