PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult the corresponding Linux  manual  page  for  details  of
       Linux behavior), or the interface may not be implemented on Linux.

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

       The functionality described on this reference page is aligned with the ISO C standard. Any
       conflict between the requirements described here and the ISO C standard is  unintentional.
       This volume of POSIX.1‐2008 defers to the ISO C standard.

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

RETURN VALUE

       The result shall have the same sign as x.

       Upon  successful  completion,  ceil(),  ceilf(),  and  ceill()  shall  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 shall be returned.

       If x is ±0 or ±Inf, x shall be returned.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

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

       These  functions  may  raise the inexact floating-point exception if the result differs in
       value from the argument.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       feclearexcept(), fetestexcept(), floor(), isnan()

       The Base Definitions volume of POSIX.1‐2008, Section 4.19, 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, 2013 Edition, Standard for Information Technology  --  Portable  Operating  System
       Interface  (POSIX),  The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc  and  The  Open  Group.   (This  is
       POSIX.1-2008  with  the  2013  Technical  Corrigendum  1  applied.)  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.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are most  likely  to  have
       been  introduced  during  the conversion of the source files to man page format. To report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .