cpp/numeric/math/fabs

@1-4@ Computes the absolute value of the floating-point value.

For integral arguments, the integral overloads of are likely better matches. If is called with an unsigned integral argument that cannot be converted to  by integral promotion, the program is ill-formed.

Return value
If successful, returns the absolute value of. The value returned is exact and does not depend on any rounding modes.

Error handling
This function is not subject to any of the error conditions specified in math_errhandling.

If the implementation supports IEEE floating-point arithmetic (IEC 60559),
 * If the argument is ±0, +0 is returned
 * If the argument is ±∞, +∞ is returned
 * If the argument is NaN, NaN is returned