fabs, fabsf, fabsl - absolute value of floating-point number
#include <math.h> double fabs(double x); float fabsf(float x); long double fabsl(long double x);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
These functions return the absolute value of the floating-point
These functions return the absolute value of
x is a NaN, a NaN is returned.
x is -0, +0 is returned.
x is negative infinity or positive infinity, positive
infinity is returned.
No errors occur.
C99, POSIX.1-2001, POSIX.1-2008.
The variant returning
double also conforms to SVr4, 4.3BSD,
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