w3resource

PHP: is_resource() function

Description

The is_resource () function is used to find whether a variable is a resource or not.

Version:

(PHP 4 and above)

Syntax:

is_resource(var_name)

Parameter:

Name Description Required /
Optional
Type
var_name The variable being checked Required Mixed*

*Mixed: Mixed indicates that a parameter may accept multiple (but not necessarily all) types.

Return value:

TRUE if var is a resource, FALSE otherwise.

Value Type: Boolean.

Example :

<?php
$fh = fopen('demo.txt','r');
if (is_resource($fh)) 
{
echo "File is open successfully......";
}
else
echo "wrong way to open a file";
?>

Output:

File is open successfully......

View the example in the browser

See also

PHP Function Reference

Previous: is_real
Next: is_scalar



PHP: Tips of the Day

SQL injection that gets around mysql_real_escape_string()

Consider the following query:

$iId = mysql_real_escape_string("1 OR 1=1");    
$sSql = "SELECT * FROM table WHERE id = $iId";

mysql_real_escape_string() will not protect you against this. The fact that you use single quotes (' ') around your variables inside your query is what protects you against this. The following is also an option:

$iId = (int)"1 OR 1=1";
$sSql = "SELECT * FROM table WHERE id = $iId";

Ref : https://bit.ly/32q3bJ7