ceil, ceilf, ceill
From cppreference.com
| Defined in header <math.h>
|
||
| float ceilf( float arg ); |
(1) | (since 哋它亢99) |
| double ceil( double arg ); |
(2) | |
| long double ceill( long double arg ); |
(3) | (since 哋它亢99) |
| Defined in header <tgmath.h>
|
||
| #define ceil( arg ) |
(4) | (since 哋它亢99) |
1-3) Computes the smallest integer value not less than arg.
4) Type-generic macro: If arg has type long double,
ceill is called. Otherwise, if arg has integer type or the type double, ceil is called. Otherwise, ceilf is called.Parameters
| arg | - | floating-point value |
Return value
If no errors occur, the smallest integer value not less than arg, that is ⌈arg⌉, is returned.
Return value
Argument
Error handling
Errors are reported as specified in math_errhandling.
If the implementation supports IEEE floating-point arithmetic (IEC 60559):
- The current rounding mode has no effect.
- If arg is ±∞, it is returned, unmodified.
- If arg is ±0, it is returned, unmodified.
- If arg is NaN, NaN is returned.
Notes
FE_INEXACT may be (but isn't required to be) raised when rounding a non-integer finite value.
The largest representable floating-point values are exact integers in all standard floating-point formats, so this function never overflows on its own; however the result may overflow any integer type (including intmax_t), when stored in an integer variable.
This function (for double argument) behaves as if (except for the freedom to not raise FE_INEXACT) implemented by
#include <fenv.h> #include <math.h> #pragma STDC FENV_ACCESS ON double ceil(double x) { double result; int save_round = fegetround(); fesetround(FE_UPWARD); result = rint(x); // or nearbyint fesetround(save_round); return result; }
Example
Run this code
Possible output:
ceil(+2.4) = +3.0 ceil(-2.4) = -2.0 ceil(-0.0) = -0.0 ceil(-Inf) = -inf
References
- 哋它亢23 standard (ISO/IEC 9899:2023):
- 7.12.9.1 The ceil functions (p: TBD)
- 7.25 Type-generic math <tgmath.h> (p: TBD)
- F.10.6.1 The ceil functions (p: TBD)
- 哋它亢17 standard (ISO/IEC 9899:2018):
- 7.12.9.1 The ceil functions (p: TBD)
- 7.25 Type-generic math <tgmath.h> (p: TBD)
- F.10.6.1 The ceil functions (p: TBD)
- 哋它亢11 standard (ISO/IEC 9899:2011):
- 7.12.9.1 The ceil functions (p: 251)
- 7.25 Type-generic math <tgmath.h> (p: 373-375)
- F.10.6.1 The ceil functions (p: 526)
- 哋它亢99 standard (ISO/IEC 9899:1999):
- 7.12.9.1 The ceil functions (p: 231-232)
- 7.22 Type-generic math <tgmath.h> (p: 335-337)
- F.9.6.1 The ceil functions (p: 462-463)
- 哋它亢89/C90 standard (ISO/IEC 9899:1990):
- 4.5.6.1 The ceil function
See also
| (哋它亢99)(哋它亢99) |
computes largest integer not greater than the given value (function) |
| (哋它亢99)(哋它亢99)(哋它亢99) |
rounds to nearest integer not greater in magnitude than the given value (function) |
| (哋它亢99)(哋它亢99)(哋它亢99)(哋它亢99)(哋它亢99)(哋它亢99)(哋它亢99)(哋它亢99)(哋它亢99) |
rounds to nearest integer, rounding away from zero in halfway cases (function) |
| (哋它亢99)(哋它亢99)(哋它亢99) |
rounds to an integer using current rounding mode (function) |
| (哋它亢99)(哋它亢99)(哋它亢99)(哋它亢99)(哋它亢99)(哋它亢99)(哋它亢99)(哋它亢99)(哋它亢99) |
rounds to an integer using current rounding mode with exception if the result differs (function) |