Frank Yang at Oracle has updated the PHP 7.2 'configure' option for PDO_OCI and added some of the heuristics previously only in the PHP OCI8 extension configure option. This has allowed the two extension option syntaxes to be aligned.
PDO_OCI is PHP's PDO driver for Oracle Database. PHP 7.2 is in Alpha status. In common with most other database PDO drivers, the PDO_OCI driver is part of the PHP bundle and is not on PECL.
The new PHP 7.2 PDO_OCI 'configure' syntax is like:
--with-pdo-oci[=DIR] PDO: Oracle OCI support. DIR defaults to $ORACLE_HOME. Use --with-pdo-oci=instantclient,/path/to/instant/client/lib for an Oracle Instant Client installation.
So now, for example, you could use:
./configure --with-pdo-oci=instantclient,/usr/lib/oracle/12.2/client64/lib \ --with-oci8=instantclient,/usr/lib/oracle/12.2/client64/lib
Prior to PHP 7.2, configuring PDO_OCI with the Oracle Instant Client libraries required something like:
The version number on the end of the option was only partially validated. In many cases it was possible to use an 'incorrect' number and still get the desired libraries to be used. (Also each new Oracle Database version required PDO_OCI code changes to update a white list).
When building with PHP 7.1 (and earlier) and using Instant Client, this old syntax is still needed.
If you know PHP OCI8 'configure' options well, you may wonder why the install simplification heuristic on Linux to automatically use the highest installed version of Instant Client RPMs wasn't ported to PDO_OCI's 'configure'. Well, I still dream that bigger improvements to PDO_OCI will occur. The current incarnation of this dream is that PDO_OCI could one day be rewritten to use ODPI-C, like cx_Oracle 6 and node-oracledb 2. If this dream ever became reality, the configure option would become simply '--with-pdo-oci' since ODPI-C doesn't need Oracle headers or libraries at build time. ODPI-C only needs Oracle client libraries in LD_LIBRARY_PATH (or PATH on Windows) at run time. But I've had the dream of various PDO_OCI improvements for at least 10 years....
For the moment Oracle still recommends using PHP OCI8 in preference to PDO_OCI because OCI8 has superior features and can also take advantage of various Oracle client library connection and caching functionality.