significand, significandf, significandl - get mantissa of floating-point number

#include <math.h>
double significand(double x);
float significandf(float x);
long double significandl(long double x);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

    /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

These functions return the mantissa of x scaled to the range [1, FLT_RADIX). They are equivalent to

scalb(x, (double) -ilogb(x))

This function exists mainly for use in certain standardized tests for IEEE 754 conformance.

ilogb(3), scalb(3)