These functions are provided for obtaining the absolute value (or
magnitude) of a number. The absolute value of a real number
x is x if x is positive, −x if x is
negative. For a complex number z, whose real part is x and
whose imaginary part is y, the absolute value is
llabs are in stdlib.h;
imaxabs is declared in inttypes.h;
fabsl are declared in math.h.
cabsl are declared in complex.h.
— Function: long int labs (long int number)
— Function: long long int llabs (long long int number)
— Function: intmax_t imaxabs (intmax_t number)
These functions return the absolute value of number.
Most computers use a two’s complement integer representation, in which the absolute value of
INT_MIN(the smallest possible
int) cannot be represented; thus,
abs (INT_MIN)is not defined.
imaxdivare new to ISO C99.
See Integers for a description of the
— Function: float cabsf (complex float z)
— Function: long double cabsl (complex long double z)
These functions return the absolute value of the complex number z (see Complex Numbers). The absolute value of a complex number is:sqrt (creal (z) * creal (z) + cimag (z) * cimag (z))
This function should always be used instead of the direct formula because it takes special care to avoid losing precision. It may also take advantage of hardware support for this operation. See
hypotin Exponents and Logarithms.