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CEIL(3P)                   POSIX Programmer's Manual                  CEIL(3P)
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 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.
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  over-
       flow.
       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 Electri-
       cal  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.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                             CEIL(3P)