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.TH MODF 3M "Jul 12, 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 TYPE	ATTRIBUTE VALUE
_
Interface Stability	Standard
_
MT-Level	MT-Safe
.TE

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