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);

       Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       floorf(), floorl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or cc -std=c99

DESCRIPTION
       These functions return the largest integral value that is not greater than x.

       For example, floor(0.5) is 0.0, and floor(-0.5) is -1.0.

RETURN VALUE
       These functions return the floor of x.

       If x is integral, +0, -0, NaN, or an infinity, x itself is returned.

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

CONFORMING TO
       C99, POSIX.1-2001.  The variant returning double also conforms to SVr4, 4.3BSD, C89.

NOTES
       SUSv2  and POSIX.1-2001 contain text about overflow (which might set errno to ERANGE, or raise an FE_OVERFLOW 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 numbers the maximum value of  the  exponent  is  128  (respec-
       tively, 1024), and the number of mantissa bits is 24 (respectively, 53).)

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

COLOPHON
       This  page  is  part of release 3.25 of the Linux man-pages project.  A description of the project, and information about
       reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



                                                           2008-10-06                                                   FLOOR(3)