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CEIL(3)                    Linux Programmer's Manual                   CEIL(3)



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

SYNOPSIS
       #include <&lt;math.h>&gt;

       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.1-2001, 4.3BSD,  C89,  C99.
       The other functions are from C99.

NOTES
       SUSv2  and  POSIX.1-2001  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 error-handling 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 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).)

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  man-pages  project.   A
       description  of  the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.



                                  2001-05-31                           CEIL(3)