FLOOR(3) Linux Programmer's Manual FLOOR(3)
floor, floorf, floorl - largest integral value not greater than argu-
double floor(double x);
float floorf(float x);
long double floorl(long double x);
Link with -lm.
These functions round x down to the nearest integer.
The rounded integer value. If x is integral or infinite, x itself is
No errors other than EDOM and ERANGE can occur. If x is NaN, then NaN
is returned and errno may be set to EDOM.
The floor() function conforms to SVr4, 4.3BSD, C89. The other func-
tions are from C99.
SUSv2 and POSIX.1-2001 contain text about overflow (which might set
errno to ERANGE, or raise an exception). In practice, the result can-
not overflow on any current machine, so this error-handling stuff is
just nonsense. (More precisely, overflow can happen only when the max-
imum 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 num-
ber of mantissa bits is 24 (respectively, 53).)
ceil(3), lrint(3), nearbyint(3), rint(3), round(3), trunc(3)
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