-q64

@PROCESS

None.

Purpose

Indicates 64-bit compilation bit mode and, together with the -qarch option, determines the target machines on which the 64-bit executable will run.

The object module is created in 64-bit object format and that the 64-bit instruction set is generated. Note that you may compile in a 32-bit environment to create 64-bit objects, but you must link them in a 64-bit environment with the -q64 option.

Syntax


>>- -q--64-----------------------------------------------------><

Defaults

Not applicable.

Rules

The default -qarch setting for -q64 is pwr4.
64-bit object modules are created when targeting 64-bit mode.
-q32 may override -q64.
The default tune setting for -q64 is -qtune=balanced:balanced.
The default integer and default real size is 4 bytes in 64-bit mode.
The default integer pointer size is 8 bytes in 64-bit mode.
The maximum array size increases to approximately 2**40 bytes (in static storage) or 2**60 bytes (in dynamic allocation on the heap). The maximum dimension bound range is extended to -2**63, 2**63-1. The maximum array size for array constants has not been extended and will remain the same as the maximum in 32-bit mode. The maximum array size that you can initialize is 2**28 bytes.
The maximum iteration count for array constructor implied DO loops increases to 2**63-1.
The maximum character variable length extends to approximately 2**40 bytes. The maximum length of character constants and subobjects of constants remains the same as in 32-bit mode, which is 32767 bytes (32 KB).
The LOC intrinsic returns an INTEGER(8) value.
If you must use -qautodbl=dblpad in 64-bit mode, you should use -qintsize=8 to promote INTEGER(4) to INTEGER(8) for 8 byte integer arithmetic.

Examples

This example targets the POWER5 in 64-bit mode:

-q32 -qarch=pwr5 -q64