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by Francesco Paolo Lovergine
rules: linking manpages-posix not manpages. |
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.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved |
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by Francesco Paolo Lovergine
* Alligned to linux main manpages edition. |
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.TH "CEIL" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" |
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by Francesco Paolo Lovergine
rules: linking manpages-posix not manpages. |
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.\" ceil |
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.SH NAME |
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ceil, ceilf, ceill \- ceiling value function
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.SH SYNOPSIS |
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.LP
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\fB#include <math.h>
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.br
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.sp
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double ceil(double\fP \fIx\fP\fB); |
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.br
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float ceilf(float\fP \fIx\fP\fB); |
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.br
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long double ceill(long double\fP \fIx\fP\fB); |
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.br
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\fP
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.SH DESCRIPTION |
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.LP
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These functions shall compute the smallest integral value not less |
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than \fIx\fP. |
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.LP
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An application wishing to check for error situations should set \fIerrno\fP |
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to zero and call |
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\fIfeclearexcept\fP(FE_ALL_EXCEPT) before calling these functions. |
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On return, if \fIerrno\fP is non-zero or |
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\fIfetestexcept\fP(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) |
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is non-zero, an error has occurred. |
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.SH RETURN VALUE |
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.LP
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Upon successful completion, \fIceil\fP(), \fIceilf\fP(), and \fIceill\fP() |
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shall return the smallest integral value not less |
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than \fIx\fP, expressed as a type \fBdouble\fP, \fBfloat\fP, or \fBlong |
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double\fP, respectively.
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.LP
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If |
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\fIx\fP is NaN, a NaN shall be returned. |
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.LP
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If \fIx\fP is \(+-0 or \(+-Inf, \fIx\fP shall be returned. |
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.LP
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If the correct value would cause overflow, a range error shall occur |
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and \fIceil\fP(), \fIceilf\fP(), and \fIceill\fP() shall |
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return the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL, |
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respectively. |
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.SH ERRORS |
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.LP
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These functions shall fail if: |
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.TP 7 |
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Range\ Error
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The result overflows. |
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.LP
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If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, |
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then \fIerrno\fP shall be set to [ERANGE]. If the |
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integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, |
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then the overflow floating-point exception shall be raised. |
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.sp
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.LP
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\fIThe following sections are informative.\fP |
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.SH EXAMPLES |
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.LP
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None. |
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.SH APPLICATION USAGE |
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.LP
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The integral value returned by these functions need not be expressible |
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as an \fBint\fP or \fBlong\fP. The return value should |
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be tested before assigning it to an integer type to avoid the undefined |
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results of an integer overflow. |
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.LP
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The \fIceil\fP() function can only overflow when the floating-point |
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representation has DBL_MANT_DIG > DBL_MAX_EXP. |
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.LP
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On error, the expressions (math_errhandling & MATH_ERRNO) and (math_errhandling |
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& MATH_ERREXCEPT) are independent of |
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each other, but at least one of them must be non-zero. |
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.SH RATIONALE |
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.LP
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None. |
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.SH FUTURE DIRECTIONS |
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.LP
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None. |
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.SH SEE ALSO |
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.LP
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\fIfeclearexcept\fP() , \fIfetestexcept\fP() , \fIfloor\fP() , \fIisnan\fP() |
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, the Base Definitions volume of |
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IEEE\ Std\ 1003.1-2001, Section 4.18, Treatment of Error Conditions |
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for |
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Mathematical Functions, \fI<math.h>\fP |
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.SH COPYRIGHT |
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Portions of this text are reprinted and reproduced in electronic form |
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology |
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-- Portable Operating System Interface (POSIX), The Open Group Base |
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of |
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Electrical and Electronics Engineers, Inc and The Open Group. In the |
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event of any discrepancy between this version and the original IEEE and |
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The Open Group Standard, the original IEEE and The Open Group Standard |
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is the referee document. The original Standard can be obtained online at |
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http://www.opengroup.org/unix/online.html . |