get_resource_type

(PHP 4 >= 4.0.2, PHP 5)

get_resource_type 返回资源(resource)类型

描述

string get_resource_type ( resource $handle )

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
?>

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User Contributed Notes 4 notes

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1
CertaiN
11 months ago
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
up
-5
avp200681 at gmail dot com
3 years ago
This function will generate an error and return NULL instead FALSE in the next example:

<?php

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

?>
up
-5
jdhawk _at_ gmail
9 years ago
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."
up
-6
hessodreamy at gmail dot com
7 years ago
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.
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