CEIL
Section: Linux Programmer's Manual (3)
Updated: 20010531
Index
Return to Main Contents
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.
NOTES
SUSv2 and POSIX.12001 contain text about overflow (which might set
errno
to ERANGE, or raise an exception).
In practice, the result cannot overflow on any current machine,
so this errorhandling 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 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).)
CONFORMING TO
The
ceil()
function conforms to SVr4, POSIX.12001, 4.3BSD, C89, C99.
The other functions are from C99.
SEE ALSO
floor(3),
lrint(3),
nearbyint(3),
rint(3),
round(3),
trunc(3)
Index
 NAME

 SYNOPSIS

 DESCRIPTION

 RETURN VALUE

 ERRORS

 NOTES

 CONFORMING TO

 SEE ALSO

linux.jgfs.net manual pages