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.\" Copyright 2001 Andries Brouwer <aeb@cwi.nl>.
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.\"
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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.\" manual page may be incorrect or out-of-date.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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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.TH CEIL 3 2001-05-31 "" "Linux Programmer's Manual"
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.SH NAME
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ceil, ceilf, ceill \- ceiling function: smallest integral value not less than argument
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.SH SYNOPSIS
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.nf
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.B #include <math.h>
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.sp
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.BI "double ceil(double " x );
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.br
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.BI "float ceilf(float " x );
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.br
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.BI "long double ceill(long double " x );
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.fi
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.sp
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Link with \-lm.
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.SH DESCRIPTION
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These functions round \fIx\fP up to the nearest integer.
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.SH "RETURN VALUE"
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The rounded integer value. If \fIx\fP is integral or infinite,
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\fIx\fP itself is returned.
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.SH ERRORS
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No errors other than EDOM and ERANGE can occur.
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If \fIx\fP is NaN, then NaN is returned and
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.I errno
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may be set to EDOM.
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.SH NOTES
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2006-08-03 13:57:30 +00:00
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SUSv2 and POSIX.1-2001 contain text about overflow (which might set
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.I errno
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to ERANGE, or raise an exception).
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In practice, the result cannot overflow on any current machine,
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so this error-handling stuff is just nonsense.
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(More precisely, overflow can happen only when the maximum value
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of the exponent is smaller than the number of mantissa bits.
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For the IEEE-754 standard 32-bit and 64-bit floating point numbers
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the maximum value of the exponent is 128 (resp. 1024), and the number
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of mantissa bits is 24 (resp. 53).)
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.SH "CONFORMING TO"
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The
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.BR ceil ()
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2006-08-03 13:57:30 +00:00
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function conforms to SVr4, POSIX.1-2001, 4.3BSD, C89, C99.
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2004-11-03 13:51:07 +00:00
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The other functions are from C99.
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.SH "SEE ALSO"
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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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.BR trunc (3)
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