c99 [ flag... ] file... –lm [ library... ] #include <math.h> double fabs(double x);
float fabsf(float x);
long double fabsl(long double x);
These functions compute the absolute value of x, |x|.
Upon successful completion, these functions return the absolute value of x.
If x is NaN, a NaN is returned.
If x is ±0, +0 is returned.
If x is ±Inf, +Inf is returned.
No errors are defined.
See attributes(5) for descriptions of the following attributes: