Name
ceil, ceilf, ceill — ceiling function: smallest integral value not less than argument
Synopsis
#include <math.h>
double
ceil( |
double x); |
float
ceilf( |
float x); |
long double
ceill( |
long double x); |
![[Note]](../stylesheet/note.png) |
Note | ||||
|---|---|---|---|---|---|
|
|
|
Note |
|---|---|
|
Link with |
DESCRIPTION
These functions return the smallest integral value that is
not less than x.
For example, ceil(0.5) is 1.0, and
ceil(−0.5) is
0.0.
RETURN VALUE
These functions return the ceiling of x.
If x is integral,
+0, −0, NaN, or infinite, x itself is returned.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
ceil(), ceilf(), ceill() |
Thread safety | MT-Safe |
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
The variant returning double also conforms to SVr4, 4.3BSD, C89.
NOTES
SUSv2 and POSIX.1-2001 contain text about overflow (which
might set errno to ERANGE, or raise an FE_OVERFLOW exception). In practice, the
result cannot overflow on any current machine, so this
error-handling stuff is just nonsense. (More precisely,
overflow can happen only when the maximum value of the
exponent is smaller than the number of mantissa bits. For the
IEEE-754 standard 32-bit and 64-bit floating-point numbers
the maximum value of the exponent is 128 (respectively,
1024), and the number of mantissa bits is 24 (respectively,
53).)
The integral value returned by these functions may be too large to store in an integer type (int, long, etc.). To avoid an overflow, which will produce undefined results, an application should perform a range check on the returned value before assigning it to an integer type.
COLOPHON
This page is part of release 4.07 of the Linux man-pages project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
|
Copyright 2001 Andries Brouwer <aebcwi.nl>. and Copyright 2008, Linux Foundation, written by Michael Kerrisk <mtk.manpagesgmail.com> %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END |