CEIL(3) Linux Programmer's Manual CEIL(3)
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);
Link with lm.
DESCRIPTION
These functions round x up to the nearest integer.
RETURN VALUE
The rounded integer value. If x is integral or infinite, x itself is
returned.
ERRORS
No errors other than EDOM and ERANGE can occur. If x is NaN, then NaN
is returned and errno may be set to EDOM.
CONFORMING TO
The ceil() function conforms to SVr4, POSIX.12001, 4.3BSD, C89, C99.
The other functions are from C99.
NOTES
SUSv2 and POSIX.12001 contain text about overflow (which might set
errno to ERANGE, or raise an exception). In practice, the result can
not overflow on any current machine, so this errorhandling stuff is
just nonsense. (More precisely, overflow can happen only when the max
imum value of the exponent is smaller than the number of mantissa bits.
For the IEEE754 standard 32bit and 64bit floating point numbers the
maximum value of the exponent is 128 (resp. 1024), and the number of
mantissa bits is 24 (resp. 53).)
SEE ALSO
floor(3), lrint(3), nearbyint(3), rint(3), round(3), trunc(3)
COLOPHON
This page is part of release 3.05 of the Linux manpages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/manpages/.
20010531 CEIL(3)
