.SH DESCRIPTION
These functions return a representation (determined by
.IR tagp )
-of a quiet NaN. If the implementation does not support
+of a quiet NaN.
+If the implementation does not support
quiet NaNs, these functions return zero.
.LP
The call
selects one.
On other systems it may do nothing.
.SH "CONFORMING TO"
-C99. See also IEC 559 and the appendix with
+C99.
+See also IEC 559 and the appendix with
recommended functions in IEEE 754/IEEE 854.
.SH "SEE ALSO"
.BR isnan (3),