XL Fortran Enterprise Edition for AIX : User's Guide - IBM

-qstrictieeemod Option
Syntax
-qstrictieeemod | -qnostrictieeemod
STRICTIEEEMOD | NOSTRICTIEEEMOD
Specifies whether the compiler will adhere to the draft Fortran 2003 IEEE
arithmetic rules for the ieee_arithmetic and ieee_exceptions intrinsic modules.
When you specify -qstrictieeemod, the compiler adheres to the following rules:
v
v
v
v
If there is an exception flag set on entry into a procedure that uses the IEEE
intrinsic modules, the flag is set on exit. If a flag is clear on entry into a
procedure that uses the IEEE intrinsic modules, the flag can be set on exit.
If there is an exception flag set on entry into a procedure that uses the IEEE
intrinsic modules, the flag clears on entry into the procedure and resets when
returning from the procedure.
When returning from a procedure that uses the IEEE intrinsic modules, the
settings for halting mode and rounding mode return to the values they had at
procedure entry.
Calls to procedures that do not use the ieee_arithmetic or ieee_exceptions
intrinsic modules from procedures that do use these modules, will not change
the floating-point status except by setting exception flags.
Since the above rules can impact performance, specifying –qnostrictieeemod will
relax the rules on saving and restoring floating-point status. This prevents any
associated impact on performance.
242 XL Fortran Enterprise Edition for AIX : User’s Guide