redhat man page for floor

FLOOR(3)						     Linux Programmer's Manual							  FLOOR(3)

NAME
       floor, floorf, floorl - largest integral value not greater than argument

SYNOPSIS
       #include <math.h>

       double floor(double x);
       float floorf(float x);
       long double floorl(long double x);

DESCRIPTION
       These functions round x down to the nearest integer.

RETURN VALUE
       The rounded integer value. If x is integral or infinite, x itself is returned.

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

NOTES
       SUSv2  and POSIX 1003.1-2001 contain text about overflow (which might set errno to ERANGE, or raise an exception).  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 num-
       bers the maximum value of the exponent is 128 (resp. 1024), and the number of mantissa bits is 24 (resp. 53).)

CONFORMING TO
       The floor() function conforms to SVID 3, POSIX, BSD 4.3, ISO 9899.  The other functions are from C99.

SEE ALSO
       ceil(3), lrint(3), nearbyint(3), rint(3), round(3), trunc(3)

								    2001-05-31								  FLOOR(3)