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CEIL(3P) POSIX Programmer's Manual CEIL(3P)PROLOGThis manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may dif- fer (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.NAMEceil, ceilf, ceill - ceiling value functionSYNOPSIS#include<math.h>doubleceil(doublex);floatceilf(floatx);longdoubleceill(longdoublex);DESCRIPTIONThese functions shall compute the smallest integral value not less thanx. An application wishing to check for error situations should seterrnoto zero and callfeclearex-cept(FE_ALL_EXCEPT) before calling these functions. On return, iferrnois non-zero orfetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred.RETURNVALUEUpon successful completion,ceil(),ceilf(), andceill() shall return the smallest integral value not less thanx, expressed as a typedouble,float, orlongdouble, respectively. Ifxis NaN, a NaN shall be returned. Ifxis ?0 or ?Inf,xshall be returned. If the correct value would cause overflow, a range error shall occur andceil(),ceilf(), andceill() shall return the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL, respectively.ERRORSThese functions shall fail if: Range Error The result overflows. If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, thenerrnoshall be set to [ERANGE]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point excep- tion shall be raised.Thefollowingsectionsareinformative.EXAMPLESNone.APPLICATIONUSAGEThe integral value returned by these functions need not be expressible as anintorlong. The return value should be tested before assigning it to an integer type to avoid the undefined results of an integer overflow. Theceil() 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 indepen- dent of each other, but at least one of them must be non-zero.RATIONALENone.FUTUREDIRECTIONSNone.SEEALSOfeclearexcept(),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>COPYRIGHTPortions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Stan- dard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifica- tions 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 Stan- dard, 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(3P)