double_t(3type)                                                double_t(3type)

NAME
       float_t, double_t - most efficient floating types

LIBRARY
       Math library (libm)

SYNOPSIS
       #include <math.h>

       typedef /* ... */ float_t;
       typedef /* ... */ double_t;

DESCRIPTION
       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_METHOD       float_t      double_t
       --------------------------------------------
              0                float        double
              1               double        double
              2          long double   long double

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

STANDARDS
       C11, POSIX.1-2008.

HISTORY
       C99, POSIX.1-2001.

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

Linux man-pages 6.7               2023-10-31                   double_t(3type)