## 3.4.35 `–fround=`{`nearest`|`tozero`|`negative`|`positive`}

Set the IEEE rounding mode in effect at startup.

The default
is` -fround=nearest`.

To be effective, compile the main program with this option.

This option sets the IEEE 754 rounding mode that:

When the value is `tozero`, `negative`,
or `positive`, the option sets the rounding direction
to **round-to-zero**, **round-to-negative-infinity**,
or **round-to-positive-infinity**, respectively, when the
program begins execution. When` -fround` is not specified,` -fround=nearest` is used as the default and the rounding direction
is **round-to-nearest**. The meanings are the same as those
for the `ieee_flags` function. (See the “Floating–Point
Arithmetic” chapter of the Fortran Programming Guide.)