.\" Copyright (c) 2004 David Schultz <das@FreeBSD.org>
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.Dd June 29, 2004
.Dt FDIM 3
.Os
.Sh NAME
.Nm fdim ,
.Nm fdimf ,
.Nm fdiml
.Nd positive difference functions
.Sh LIBRARY
.Lb libm
.Sh SYNOPSIS
.In math.h
.Ft double
.Fn fdim "double x" "double y"
.Ft float
.Fn fdimf "float x" "float y"
.Ft long double
.Fn fdiml "long double x" "long double y"
.Sh DESCRIPTION
The
.Fn fdim ,
.Fn fdimf ,
and
.Fn fdiml
functions return the positive difference between
.Fa x
and
.Fa y .
That is, if
.Fa x\- Ns Fa y
is positive, then
.Fa x\- Ns Fa y
is returned.
If either
.Fa x
or
.Fa y
is an \*(Na, then an \*(Na is returned.
Otherwise, the result is
.Li +0.0 .
.Pp
Overflow or underflow may occur if the exact result is not
representable in the return type.
No other exceptions are raised.
.Sh SEE ALSO
.Xr fabs 3 ,
.Xr fmax 3 ,
.Xr fmin 3 ,
.Xr math 3
.Sh STANDARDS
The
.Fn fdim ,
.Fn fdimf ,
and
.Fn fdiml
functions conform to
.St -isoC-99 .
.Sh HISTORY
These routines first appeared in
.Fx 5.3 .