addcslashes

(PHP 4, PHP 5)

addcslashes — Quote string with slashes in a C style

Description

string addcslashes ( string $str , string $charlist )

Returns a string with backslashes before characters that are listed in charlist parameter.

Parameters

str

The string to be escaped.

charlist

A list of characters to be escaped. If charlist contains characters \n, \r etc., they are converted in C-like style, while other non-alphanumeric characters with ASCII codes lower than 32 and higher than 126 converted to octal representation.

When you define a sequence of characters in the charlist argument make sure that you know what characters come between the characters that you set as the start and end of the range.

<?php
echo addcslashes('foo[ ]', 'A..z');
// output:  \f\o\o\[ \]
// All upper and lower-case letters will be escaped
// ... but so will the [\]^_`
?>
Also, if the first character in a range has a higher ASCII value than the second character in the range, no range will be constructed. Only the start, end and period characters will be escaped. Use the ord() function to find the ASCII value for a character.
<?php
echo addcslashes("zoo['.']", 'z..A');
// output:  \zoo['\.']
?>

Be careful if you choose to escape characters 0, a, b, f, n, r, t and v. They will be converted to \0, \a, \b, \f, \n, \r, \t and \v. In PHP \0 (NULL), \r (carriage return), \n (newline), \f (form feed), \v (vertical tab) and \t (tab) are predefined escape sequences, while in C all of these are predefined escape sequences.

Return Values

Returns the escaped string.

Changelog

Version Description
5.2.5 The escape sequences \v and \f were added.

Examples

charlist like "\0..\37", which would escape all characters with ASCII code between 0 and 31.

Example #1 addcslashes() example

<?php
$escaped = addcslashes($not_escaped, "\0..\37!@\177..\377");
?>

See Also