mirror of https://github.com/mkerrisk/man-pages
101 lines
2.6 KiB
Groff
101 lines
2.6 KiB
Groff
.\" Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>.
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.\"
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.\" %%%LICENSE_START(VERBATIM)
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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.\"
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\" %%%LICENSE_END
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.\"
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.TH TRUNC 3 2019-03-06 "" "Linux Programmer's Manual"
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.SH NAME
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trunc, truncf, truncl \- round to integer, toward zero
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.SH SYNOPSIS
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.nf
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.B #include <math.h>
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.PP
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.BI "double trunc(double " x );
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.BI "float truncf(float " x );
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.BI "long double truncl(long double " x );
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.fi
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.PP
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Link with \fI\-lm\fP.
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.PP
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.in -4n
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Feature Test Macro Requirements for glibc (see
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.BR feature_test_macros (7)):
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.in
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.PP
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.ad l
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.BR trunc (),
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.BR truncf (),
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.BR truncl ():
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.RS 4
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_ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L
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.RE
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.ad
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.SH DESCRIPTION
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These functions round
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.I x
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to the nearest integer value that is not larger in magnitude than
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.IR x .
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.SH RETURN VALUE
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These functions return the rounded integer value, in floating format.
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.PP
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If
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.I x
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is integral, infinite, or NaN,
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.I x
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itself is returned.
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.SH ERRORS
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No errors occur.
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.SH VERSIONS
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These functions first appeared in glibc in version 2.1.
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.SH ATTRIBUTES
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For an explanation of the terms used in this section, see
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.BR attributes (7).
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.TS
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allbox;
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lbw27 lb lb
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l l l.
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Interface Attribute Value
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T{
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.BR trunc (),
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.BR truncf (),
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.BR truncl ()
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T} Thread safety MT-Safe
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.TE
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.SH CONFORMING TO
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C99, POSIX.1-2001, POSIX.1-2008.
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.SH NOTES
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The integral value returned by these functions may be too large
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to store in an integer type
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.RI ( int ,
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.IR long ,
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etc.).
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To avoid an overflow, which will produce undefined results,
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an application should perform a range check on the returned value
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before assigning it to an integer type.
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.SH SEE ALSO
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.BR ceil (3),
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.BR floor (3),
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.BR lrint (3),
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.BR nearbyint (3),
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.BR rint (3),
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.BR round (3)
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