mirror of https://github.com/mkerrisk/man-pages
55 lines
1.6 KiB
Groff
55 lines
1.6 KiB
Groff
.\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
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.\" Distributed under GPL
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.\" Based on glibc infopages
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.TH NEXTAFTER 3 2002-08-10 "GNU" "Linux Programmer's Manual"
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.SH NAME
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nextafter, nextafterf, nextafterl, nexttoward, nexttowardf, nexttowardl \-
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floating point number manipulation
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.SH SYNOPSIS
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.B #include <math.h>
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.sp
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.BI "double nextafter(double " x ", double " y );
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.br
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.BI "float nextafterf(float " x ", float " y );
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.br
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.BI "long double nextafterl(long double " x ", long double " y );
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.sp
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.BI "double nexttoward(double " x ", long double " y );
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.br
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.BI "float nexttowardf(float " x ", long double " y );
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.br
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.BI "long double nexttowardl(long double " x ", long double " y );
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.sp
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Link with \fI-lm\fP.
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.SH DESCRIPTION
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The
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.BR nextafter ()
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functions return the next representable neighbor of
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\fIx\fP in the direction towards \fIy\fP.
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The size of the step
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between \fIx\fP and the result depends on the type of the result.
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If \fIx\fP = \fIy\fP the function simply returns \fIy\fP.
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If either value is
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.IR NaN ,
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then
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.I NaN
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is returned.
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Otherwise a value corresponding to the value of the
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least significant bit in the mantissa is added or subtracted,
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depending on the direction.
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.PP
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The
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.BR nexttoward ()
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functions do the same as the
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.BR nextafter ()
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functions, except that they have a long double second argument.
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.PP
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These functions will signal overflow or underflow if the result
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goes outside of the range of normalized numbers.
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.SH "CONFORMING TO"
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C99.
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This function is defined in IEC 559 (and the appendix with
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recommended functions in IEEE 754/IEEE 854).
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.SH "SEE ALSO"
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.BR nearbyint (3)
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