c99 [ flag... ] file... –lm [ library... ] #include <math.h> double floor(double x);
float floorf(float x);
long double floorl(long double x);
These functions compute the largest integral value not greater than x.
Upon successful completion, these functions return the largest integral value not greater than x, expressed as a double, float, or long double, as appropriate for the return type of the function.
If x is NaN, a NaN is returned.
If x is ±Inf or ±0, x is returned.
See attributes(5) for descriptions of the following attributes: