LDAP support in PHP is not enabled by default. You will need to use the --with-ldap[=DIR] configuration option when compiling PHP to enable LDAP support. DIR is the LDAP base install directory. To enable SASL support, be sure --with-ldap-sasl[=DIR] is used, and that sasl.h exists on the system.
Note: Note to Win32 Users
为了使此扩展生效， DLL 文件必须能在 Windows 系统的 PATH 指示的路径下找到。如何操作的信息，请参见题为“如何在 Windows 中将 PHP 目录加到 PATH 中”的FAQ。虽然将 DLL 文件从 PHP 文件夹复制到 Windows 系统目录也行，但不建议这样做。 此扩展需要下列文件在 PATH 路径中： libeay32.dll and ssleay32.dll, or, as of OpenSSL 1.1 libcrypto-*.dll and libssl-*.dll
In order to use Oracle LDAP libraries, proper Oracle environment has to be set.