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man pages section 3: Extended Library Functions, Volume 2

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Updated: Thursday, June 13, 2019
 
 

ceil(3M)

Name

ceil, ceilf, ceill - ceiling value function

Synopsis

c99 [ flag... ] file... –lm [ library... ]
#include <math.h>

double ceil(double x);
float ceilf(float x);
long double ceill(long double x);

Description

These functions compute the smallest integral value not less than x.

Return Values

Upon successful completion, the ceil(), ceilf(), and ceill() functions return the smallest integral value not less than x, expressed as a type double, float, or long double, respectively.

If x is NaN, a NaN is returned.

If x is ±0 or ±Inf, x is returned.

Usage

The integral value returned by these functions need not be expressible as an int or long int. The return value should be tested before assigning it to an integer type to avoid the undefined results of an integer overflow.

Attributes

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
Interface Stability
Committed
Availability
system/library/math
MT-Level
MT-Safe
Standard

See Also

math.h(3HEAD), feclearexcept(3M), fetestexcept(3M), floor(3M), isnan(3M), attributes(7), standards(7)