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 |
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.
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
http://en.cppreference.com/w/c/types/limits/FLT_EVAL_METHOD