'\" te
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.TH erf 3M "12 Jul 2006" "SunOS 5.11" "Mathematical Library Functions"
.SH NAME
erf, erff, erfl \- error function
.SH SYNOPSIS
.LP
.nf
c99 [ \fIflag\fR... ] \fIfile\fR... \fB-lm\fR [ \fIlibrary\fR... ]
#include <math.h>

\fBdouble\fR \fBerf\fR(\fBdouble\fR \fIx\fR);
.fi

.LP
.nf
\fBfloat\fR \fBerff\fR(\fBfloat\fR \fIx\fR);
.fi

.LP
.nf
\fBlong double\fR \fBerfl\fR(\fBlong double\fR \fIx\fR);
.fi

.SH DESCRIPTION
.sp
.LP
These functions compute the error function of their argument \fIx\fR, defined
as:
.sp
2/sqrt(pi)*intregral from 0 to x of exp(-t*t) dt
.SH RETURN VALUES
.sp
.LP
Upon successful completion, these functions return the value of the error
function.
.sp
.LP
If \fIx\fR is NaN, a NaN is returned.
.sp
.LP
If \fIx\fR is \(+-0, \(+-0 is returned.
.sp
.LP
If \fIx\fR is \(+-Inf, \(+-1 is returned.
.sp
.LP
If \fIx\fR is subnormal, 2/sqrt(\c
.if n pi\c
.if t \(*p
\c
) * 2 is returned.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
tab() box;
cw(2.75i) |cw(2.75i) 
lw(2.75i) |lw(2.75i) 
.
ATTRIBUTE TYPEATTRIBUTE VALUE
_
Interface StabilityStandard
_
MT-LevelMT-Safe
.TE

.SH SEE ALSO
.sp
.LP
\fBerfc\fR(3M), \fBfeclearexcept\fR(3M), \fBfetestexcept\fR(3M),
\fBisnan\fR(3M), \fBmath.h\fR(3HEAD), \fBattributes\fR(5), \fBstandards\fR(5)