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

PHP - how to create a newline character?

Only double quoted strings interpret the escape sequences \r and \n as '0x0D' and '0x0A' respectively, so you want:

"\r\n"

Single quoted strings, on the other hand, only know the escape sequences \\ and \'.

So unless you concatenate the single quoted string with a line break generated elsewhere (e. g., using double quoted string "\r\n" or using chr function chr(0x0D).chr(0x0A)), the only other way to have a line break within a single quoted string is to literally type it with your editor:

$s = 'some text before the line break
some text after';

Make sure to check your editor for its line break settings if you require some specific character sequence (\r\n for example).

Ref : https://bit.ly/3hcyege