FLT_EVAL_METHOD
From cppreference.com
| Defined in header <float.h>
|
||
| #define FLT_EVAL_METHOD /* implementation defined */ |
(since C99) | |
Specifies range and precision of floating-point values obtained from floating-point constants and from all operations (operators, implicit conversions of operands) except assignment, cast, and library function call.
| Value | Explanation |
negative values except -1
|
implementation-defined behavior |
-1
|
the default precision is not known |
0
|
all operations and constants evaluate in the range and precision of the type used. Additionally, float_t and double_t are equivalent to float and double respectively |
1
|
all operations and constants evaluate in the range and precision of double. Additionally, both float_t and double_t are equivalent to double |
2
|
all operations and constants evaluate in the range and precision of long double. Additionally, both float_t and double_t are equivalent to long double |
Notes
Regardless of the value of FLT_EVAL_METHOD, any floating-point expression may be contracted, that is, calculated as if all intermediate results have infinite range and precision (unless #pragma STDC FP_CONTRACT is off)
Cast and assignment strip away any extraneous range and precision: this models the action of storing a value from an extended-precision FPU register into a standard-sized memory location.
See also
| (C99)(C99) |
most efficient floating-point type at least as wide as float or double (typedef) |