mirror of https://github.com/mkerrisk/man-pages
85 lines
2.5 KiB
Plaintext
85 lines
2.5 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "MODF" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" modf
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.SH PROLOG
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This manual page is part of the POSIX Programmer's Manual.
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The Linux implementation of this interface may differ (consult
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the corresponding Linux manual page for details of Linux behavior),
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or the interface may not be implemented on Linux.
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.SH NAME
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modf, modff, modfl \- decompose a floating-point number
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.SH SYNOPSIS
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.LP
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\fB#include <math.h>
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.br
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.sp
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double modf(double\fP \fIx\fP\fB, double *\fP\fIiptr\fP\fB);
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.br
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float modff(float\fP \fIvalue\fP\fB, float *\fP\fIiptr\fP\fB);
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.br
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long double modfl(long double\fP \fIvalue\fP\fB, long double *\fP\fIiptr\fP\fB);
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.br
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\fP
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.SH DESCRIPTION
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.LP
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These functions shall break the argument \fIx\fP into integral and
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fractional parts, each of which has the same sign as the
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argument. It stores the integral part as a \fBdouble\fP (for the \fImodf\fP()
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function), a \fBfloat\fP (for the \fImodff\fP()
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function), or a \fBlong double\fP (for the \fImodfl\fP() function),
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in the object pointed to by \fIiptr\fP.
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.SH RETURN VALUE
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.LP
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Upon successful completion, these functions shall return the signed
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fractional part of \fIx\fP.
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.LP
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If
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\fIx\fP is NaN, a NaN shall be returned, and *\fIiptr\fP shall be
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set to a NaN.
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.LP
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If \fIx\fP is \(+-Inf, \(+-0 shall be returned, and *\fIiptr\fP shall
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be set to \(+-Inf.
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.SH ERRORS
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.LP
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No errors are defined.
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.LP
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\fIThe following sections are informative.\fP
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.SH EXAMPLES
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.LP
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None.
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.SH APPLICATION USAGE
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.LP
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The \fImodf\fP() function computes the function result and *\fIiptr\fP
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such that:
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.sp
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.RS
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.nf
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\fBa = modf(x, iptr) ;
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x == a+*iptr ;
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\fP
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.fi
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.RE
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.LP
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allowing for the usual floating-point inaccuracies.
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.SH RATIONALE
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.LP
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None.
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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\fIfrexp\fP(), \fIisnan\fP(), \fIldexp\fP(),
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the Base Definitions volume of IEEE\ Std\ 1003.1-2001, \fI<math.h>\fP
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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