ceil, ceilf, ceill - ceiling function: smallest integral value not less than argument

#include <math.h>
 I double ceil(double  x );

I float ceilf(float  x );

I long double ceill(long double  x );

Link with -lm.

These functions round x up to the nearest integer.

The rounded integer value. If x is integral or infinite, x itself is returned.

No errors other than EDOM and ERANGE can occur. If x is NaN, then NaN is returned and errno may be set to EDOM.

The R ceil () function conforms to SVr4, POSIX.1-2001, 4.3BSD, C89, C99. The other functions are from C99.

SUSv2 and POSIX.1-2001 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 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 (resp. 1024), and the number of mantissa bits is 24 (resp. 53).)

floor(3), lrint(3), nearbyint(3), rint(3), round(3), trunc(3)