float_t, double_t - most efficient floating types

       The  implementation's  most  efficient  floating types at least as wide as float and double respectively.
       Their type depends on the value of the macro FLT_EVAL_METHOD (defined in <float.h>):

       FLT_EVAL_METHODfloat_tdouble_t
       ────────────────────────────────────────────
              0                floatdouble
              1               doubledouble
              2          longdoublelongdouble

       For other values of FLT_EVAL_METHOD, the types of float_t and double_t are implementation-defined.

       C99, POSIX.1-2001.

       Math library (libm)

       float_t, double_t - most efficient floating types

float.h(0p), math.h(0p)

Linux man-pages 6.9.1                              2024-05-02                                    double_t(3type)

       C11, POSIX.1-2008.

#include<math.h>typedef /* ... */ float_t;typedef /* ... */ double_t;