Advanced installation

It is highly recommended that you install IBM® XL C/C++ for Blue Gene®/Q, V12.1 to the default location and use the procedure provided in Basic installation.

You want to maintain more than one version of IBM XL C/C++ for Blue Gene/Q on the same system.
You want to upgrade or update an existing version of IBM XL C/C++ for Blue Gene/Q that is installed in a nondefault location.
You want to try out a new update of the compiler before removing an existing installation from the default location.
The Blue Gene/Q tool chain is installed in the default location, /bgsys/drivers/ppcfloor.

In all of these scenarios, you can use the rpm utility to install the compiler packages; you can also use the xlc_install utility to install the compiler packages to a single, nondefault location. This nondefault location must be under the root directory /bgsys/xlcompilers. After you have successfully installed the compiler packages to a nondefault location using the rpm utility, you need to manually configure the compiler environment using the new_install or vac_configure utility. For configuration procedures, see Configuring IBM XL C/C++ for Blue Gene/Q, V12.1 (for advanced users).