php man page for addslashes

ADDSLASHES(3)								 1							     ADDSLASHES(3)

addslashes - Quote string with slashes

SYNOPSIS
       string addslashes (string  $str)

DESCRIPTION
	Returns  a  string  with backslashes before characters that need to be escaped. These characters are single quote ( '), double quote ( "),
       backslash ( ) and NUL (the NULL byte).

	An example use of addslashes(3) is when you're entering data into string that is evaluated by PHP. For	example,  O'Reilly  is	stored	in
       $str, you need to escape $str. (e.g. eval("echo '".addslashes($str)."';"); )

	To  escape  database  parameters,  DBMS  specific  escape  function  (e.g. mysqli_real_escape_string(3) for MySQL or pg_escape_literal(3),
       pg_escape_string(3) for PostgreSQL) should be used for security reasons. DBMSes have differect escape specification for	identifiers  (e.g.
       Table name, field name) than parameters. Some DBMS such as PostgreSQL provides identifier escape function, pg_escape_identifier(3), but not
       all DBMS provides identifier escape API. If this is the case, refer to your database system manual for proper escaping method.

	If your DBMS doesn't have an escape function and the DBMS uses  to escape special chars, you might be able to use this function only when
       this  escape  method  is  adequate for your database. Please note that use of addslashes(3) for database parameter escaping can be cause of
       security issues on most databases.

	The PHP directive  magic_quotes_gpc was on by default before PHP 5.4, and it essentially ran addslashes(3) on all GET,	POST,  and  COOKIE
       data. Do not use addslashes(3) on strings that have already been escaped with magic_quotes_gpc as you'll then do double escaping. The func-
       tion get_magic_quotes_gpc(3) may come in handy for checking this.

PARAMETERS
	      o $str
		- The string to be escaped.

RETURN VALUES
	Returns the escaped string.

EXAMPLES
       Example #1

	      An addslashes(3) example

	      <?php
	      $str = "Is your name O'Reilly?";

	      // Outputs: Is your name O'Reilly?
	      echo addslashes($str);
	      ?>

SEE ALSO
       stripcslashes(3), stripslashes(3), addcslashes(3), htmlspecialchars(3), quotemeta(3), get_magic_quotes_gpc(3).

PHP Documentation Group 													     ADDSLASHES(3)