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[thirdparty/man-pages.git] / man3 / fma.3

.\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
.\" Distributed under GPL, 2002-07-27 Walter Harms
.\" Modified 2004-11-15, Added further text on FLT_ROUNDS
.\" 	as suggested by AEB and Fabian Kreutz
.\"
.TH FMA 3  2002-07-27 "" "Linux Programmer's Manual"
.SH NAME
fma, fmaf, fmal \- floating-point multiply and add
.SH SYNOPSIS
.nf
.B #include <math.h>
.sp
.BI "double fma(double " x ", double " y ", double " z );
.br
.BI "float fmaf(float " x ", float " y ", float " z );
.br
.BI "long double fmal(long double " x ", long double " y ", long double " z );
.fi
.sp
Compile with \-std=c99; link with \-lm.
.SH DESCRIPTION
The  
.BR fma ()
function computes
.IR x " * " y " + " z .
The result is rounded according to the
rounding mode determined by the value of FLT_ROUNDS.
FLT_ROUNDS indicates the implementation-defined rounding
behaviour for floating-point addition,
and has one of the following values:
.IP \-1
The rounding mode is not determinable.
.IP 0
Rounding is towards 0.
.IP 1
Rounding is towards nearest number.
.IP 2
Rounding is towards positive infinity.
.IP 3
Rounding is towards negative infinity.
.PP
Other values represent machine-dependent, non-standard rounding modes.
.SH "CONFORMING TO"
C99
.SH "SEE ALSO"
.BR fenv (3),
.BR remainder (3),
.BR remquo (3)