float_log

Summary. Return the base-10 logarithm of an XFL.

Signature.

int64_t float_log(int64_t float1);

Parameters.

Name	Type	Description
float1	int64_t	The XFL to take the logarithm of.

Return value. log10(float1) as an XFL. Errors: INVALID_FLOAT (-10024) if float1 is invalid; INVALID_ARGUMENT (-7) if float1 is the XFL 0; COMPLEX_NOT_SUPPORTED (-39) if float1 is negative.

Common failure patterns.

• log of 0 → INVALID_ARGUMENT; of a negative → COMPLEX_NOT_SUPPORTED.

Caveats / notes.

• This is the base-10 logarithm: the implementation computes log10(mantissa) + exponent. (Some older references describe it as a natural log; the code uses base 10.)
• The result is computed with a double internally, so it carries floating-point rounding — do not rely on it for exact financial equality.

Minimal example.

int64_t l = float_log(float_set(0, 1000));   // log10(1000) ~= 3

Related APIs. float_root, float_multiply.