Default bit mode

The AIX® operating system provides support for the OBJECT_MODE environment variable to enable the user to obtain a 64-bit development environment. AIX tools use the setting of OBJECT_MODE to determine the type of object to be used or created. The OBJECT_MODE environment variable has three recognized settings:
OBJECT_MODE=32
Works with 32-bit objects
OBJECT_MODE=64
Works with 64-bit objects
OBJECT_MODE=32_64
Works with either 32-bit or 64-bit objects
The XL Fortran compiler determines the default bit mode through the setting of the OBJECT_MODE environment variable at the time of invocation. The following table shows the default bit mode and options that are set for each setting of the OBJECT_MODE environment variable:
Table 1. Default bit mode determined by the setting of OBJECT_MODE
OBJECT_MODE Setting Default Bit Mode Default Option Set
unset 32-bit -q32
32 32-bit -q32
64 64-bit -q64
32_64 Not permitted n/a
Specification of the following options on the command line or in the configuration file overrides the default option set:

Important note

Using OBJECT_MODE to determine the default bit mode can have serious implications if you are not aware of the setting of OBJECT_MODE at the time of invocation. For example, you may not be aware that OBJECT_MODE has been set to 64, and you may unexpectedly obtain 64-bit object files.

We strongly urge you to be aware of the setting of OBJECT_MODE at all times and to set it yourself to ensure that the compiler is invoked for the correct bit mode. Alternatively, you can always use the -q32 or -q64 option to specify the bit mode.