ceill(3)

1CEIL(3)                    Linux Programmer's Manual                   CEIL(3)
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NAME

6       ceil, ceilf, ceill - ceiling function: smallest integral value not less
7       than argument
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SYNOPSIS

10       #include <math.h>
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12       double ceil(double x);
13       float ceilf(float x);
14       long double ceill(long double x);
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16       Link with -lm.
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DESCRIPTION

19       These functions round x up to the nearest integer.
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RETURN VALUE

22       The rounded integer value. If x is integral or infinite,  x  itself  is
23       returned.
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ERRORS

26       No  errors other than EDOM and ERANGE can occur.  If x is NaN, then NaN
27       is returned and errno may be set to EDOM.
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NOTES

30       SUSv2 and POSIX.1-2001 contain text about  overflow  (which  might  set
31       errno  to ERANGE, or raise an exception).  In practice, the result can‐
32       not overflow on any current machine, so this  error-handling  stuff  is
33       just nonsense.  (More precisely, overflow can happen only when the max‐
34       imum value of the exponent is smaller than the number of mantissa bits.
35       For  the IEEE-754 standard 32-bit and 64-bit floating point numbers the
36       maximum value of the exponent is 128 (resp. 1024), and  the  number  of
37       mantissa bits is 24 (resp. 53).)
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CONFORMING TO

40       The  ceil()  function conforms to SVr4, POSIX.1-2001, 4.3BSD, C89, C99.
41       The other functions are from C99.
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