CEIL(P) 						     POSIX Programmer's Manual							   CEIL(P)

NAME

       ceil, ceilf, ceill - ceiling value function

SYNOPSIS

       #include <math.h>

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

DESCRIPTION

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

       An  application	wishing  to check for error situations should set errno to zero and call feclearexcept(FE_ALL_EXCEPT) before calling these
       functions.  On return, if errno is non-zero or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero,  an  error
       has occurred.

RETURN VALUE

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

       If x is NaN, a NaN shall be returned.

       If x is +-0 or +-Inf, x shall be returned.

       If the correct value would cause overflow, a range error shall occur and ceil(), ceilf(), and ceill() shall return the value of	the  macro
       HUGE_VAL, HUGE_VALF, and HUGE_VALL, respectively.

ERRORS

       These functions shall fail if:

       Range Error
	      The result overflows.

       If  the	integer  expression  (math_errhandling	&  MATH_ERRNO) is non-zero, then errno shall be set to [ERANGE]. If the integer expression
       (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point exception shall be raised.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

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

       The ceil() function can only overflow when the floating-point representation has DBL_MANT_DIG > DBL_MAX_EXP.

       On  error,  the	expressions  (math_errhandling & MATH_ERRNO) and (math_errhandling & MATH_ERREXCEPT) are independent of each other, but at
       least one of them must be non-zero.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       feclearexcept() , fetestexcept() , floor() , isnan() , the Base Definitions volume of  IEEE Std 1003.1-2001,  Section  4.18,  Treatment	of
       Error Conditions for Mathematical Functions, <math.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical  and	Electronics  Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE
       and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can  be  obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003								   CEIL(P)