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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."

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get_resource_type

描述

User Contributed Notes

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