w3resource

PHP: is_bool() function

Description

The is_bool() function is used to find whether a variable is an a boolean or not.

Version:

(PHP 4 and above)

Syntax:

is_bool (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_name is a boolean, FALSE otherwise.

Value Type: Boolean.

Example:

<?php
$var_name=false;
if (is_bool($var_name))
echo 'This is a boolean.';
else
echo 'This is not a boolean.';
?>

Output :

This is a boolean.

View the example in the browser

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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