PHP Warning: PHP Startup: Unable to load dynamic library 'c:\\php\\ext\\php_ldap.dll'

Question

Windows 7 apache 2.4 php 5.6.31

c:/windows/php.ini

extension_dir = "c:\php\ext"

extension=php_gd2.dll
extension=php_ldap.dll
extension=php_mysql.dll
extension=php_mysqli.dll
extension=php_pdo_sqlite.dll

gd2,mysql,mysqli, php_pdo_sqlite work. php_ldap.dll daesn't works.

apache error.log:

PHP Warning:  PHP Startup: Unable to load dynamic library 'c:\\php\\ext\\php_ldap.dll'