None.
Selects either 32-bit or 64-bit compiler mode.
Use the -q32 and -q64 options, along with the -qarch and -qtune compiler options, to optimize the output of the compiler to the architecture on which that output will be used.
-q32
The -q32 and -q64 options override the compiler mode set by the value of the OBJECT_MODE environment variable, if it exists.
When -q64 is in effect, __64BIT__ is defined to 1; otherwise, it is undefined.
To specify that the executable program testing compiled from myprogram.c is to run on a computer with a 64-bit Power® architecture, enter:
xlc -o testing myprogram.c -q64 -qarch=ppc