ceil(3) – Linux man page

SUSv2 and POSIX.1-2001 contain text about overflow (which might seterrnotoERANGE, or raise anFE_OVERFLOWexception). In practice, the result cannot overflow on any current machine, so this error-handling stuff is just nonsense. (More precisely, overflow can happen only when the maximum value of the exponent is smaller than the number of mantissa bits. For the IEEE-754 standard 32-bit and 64-bit floating-point numbers the maximum value of the exponent is 128 (respectively, 1024), and the number of mantissa bits is 24 (respectively, 53).)

These functions return the ceiling ofx.

ceil, ceilf, ceill – ceiling function: smallest integral value not less than argumentinclude math.h double ceil(double

ceil(3) - Linux man page

Feature Test Macro Requirements for glibc (seefeature_test_macros(7)):ceilf(),ceill():_BSD_SOURCE _SVID_SOURCE _XOPEN_SOURCE = 600 _ISOC99_SOURCE _POSIX_C_SOURCE = 200112L;

No errors occur. POSIX.1-2001 documents a range error for overflows, but see NOTES.Conforming To

These functions return the smallest integral value that is not less thanx.

The integral value returned by these functions may be too large to store in an integer type (int,long, etc.). To avoid an overflow, which will produce undefined results, an application should perform a range check on the returned value before assigning it to an integer type.See Also

For example,ceil(0.5)is 1.0, andceil(-0.5)is 0.0.Return Value

Ifxis integral, +0, -0, NaN, or infinite,xitself is returned.Errors

C99, POSIX.1-2001. The variant returningdoublealso conforms to SVr4, 4.3BSD, C89.Notes

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