'\" te
.\" Copyright (c) 2001, the Institute of Electrical and Electronics Engineers, Inc. and The Open Group. All Rights Reserved.
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.TH modf 3M "12 Jul 2006" "SunOS 5.11" "Mathematical Library Functions"
.SH NAME
modf, modff, modfl \- decompose floating-point number
.SH SYNOPSIS
.LP
.nf
c99 [ \fIflag\fR... ] \fIfile\fR... \fB-lm\fR [ \fIlibrary\fR... ]
#include <math.h>

\fBdouble\fR \fBmodf\fR(\fBdouble\fR \fIx\fR, \fBdouble *\fR\fIiptr\fR);
.fi

.LP
.nf
\fBfloat\fR \fBmodff\fR(\fBfloat\fR \fIx\fR, \fBfloat *\fR\fIiptr\fR);
.fi

.LP
.nf
\fBlong double\fR \fBmodfl\fR(\fBlong double\fR \fIx\fR, \fBlong double *\fR\fIiptr\fR);
.fi

.SH DESCRIPTION
.sp
.LP
These functions break the argument \fIx\fR into integral and fractional parts, each of which has the same sign as the argument. It stores the integral part as a \fBdouble\fR for the \fBmodf()\fR function, a float for the \fBmodff()\fR function, or a long double for the\fBmodfl()\fR function in the object pointed to by \fIiptr\fR.
.SH RETURN VALUES
.sp
.LP
Upon successful completion, these functions return the signed fractional part of \fIx\fR.
.sp
.LP
If \fIx\fR is NaN, a NaN is returned and *\fIiptr\fR is set to NaN.
.sp
.LP
If \fIx\fR is \(+-Inf, \(+-0 is returned and *\fIiptr\fR is set to \(+-Inf.
.SH ERRORS
.sp
.LP
No errors are defined.
.SH USAGE
.sp
.LP
These functions compute the function result and *\fIiptr\fR such that:
.sp
.in +2
.nf
a = modf(x, &iptr) ;
x == a+*iptr ;
.fi
.in -2

.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 StabilityCommitted
_
MT-LevelMT-Safe
_
StandardSee \fBstandards\fR(5).
.TE

.SH SEE ALSO
.sp
.LP
\fBfrexp\fR(3M), \fBisnan\fR(3M), \fBldexp\fR(3M), \fBattributes\fR(5), \fBstandards\fR(5)