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:
ATTRIBUTE TYPE | ATTRIBUTE VALUE |
Interface Stability | Standard |
MT-Level | MT-Safe |
ceil(3M), feclearexcept(3M), fetestexcept(3M), isnan(3M), math.h(3HEAD), attributes(5), standards(5)