[edit]Parameters

[edit]Return value

If no errors occur, the smallest integer value not less thanarg, that is⌈arg⌉, is returned.

Return value

Argument

[edit]Error handling

Errors are reported as specified inmath_errhandling.

If the implementation supports IEEE floating-point arithmetic (IEC 60559):

• The currentrounding mode has no effect.
• Ifarg is ±∞, it is returned, unmodified.
• Ifarg is ±0, it is returned, unmodified.
• Ifarg is NaN, NaN is returned.

[edit]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 (includingintmax_t), when stored in an integer variable.

This function (fordouble argument) behaves as if (except for the freedom to not raiseFE_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 nearbyintfesetround(save_round);return result;}

[edit]Example

#include <math.h>#include <stdio.h> int main(void){printf("ceil(+2.4) = %+.1f\n", ceil(2.4));printf("ceil(-2.4) = %+.1f\n", ceil(-2.4));printf("ceil(-0.0) = %+.1f\n", ceil(-0.0));printf("ceil(-Inf) = %+f\n",   ceil(-INFINITY));}

ceil(+2.4) = +3.0ceil(-2.4) = -2.0ceil(-0.0) = -0.0ceil(-Inf) = -inf

[edit]References

[edit]See also

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