-fround=r

Sets the IEEE rounding mode in effect at start-up.

This option sets the IEEE 754 rounding mode that:

• Can be used by the compiler in evaluating constant expressions

• Is established at runtime during the program initialization

The meanings are the same as those for the ieee_flags subroutine, which can be used to change the mode at runtime.

Values

r must be one of the following:

Defaults

When the -fround option is not specified, the rounding mode defaults to -fround=nearest.

Warnings

If you compile one routine with -fround=r, compile all routines of the program with the same -fround=r option; otherwise, you might get unexpected results.

This option is effective only if used when compiling the main program.