get_defined_vars
This function will generate an error and return NULL instead FALSE in the next example:
<?php
$var = 3;
var_dump(get_resource_type($var));
?>
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
get_resource_type - [3 notes]
avp200681 at gmail dot com ¶
1 year ago
hessodreamy at gmail dot com ¶
5 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.
jdhawk _at_ gmail ¶
7 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."