Namespaces
Variants
Views
Actions

FLT_EVAL_METHOD

From cppreference.com
< cpp‎ | types‎ | climits
 
 
Utilities library
General utilities
Date and time
Function objects
Formatting library (C++20)
(C++11)
Relational operators (deprecated in C++20)
Integer comparison functions
(C++20)(C++20)(C++20)   
(C++20)
Swap and type operations
(C++14)
(C++11)
(C++11)
(C++11)
(C++17)
Common vocabulary types
(C++11)
(C++17)
(C++17)
(C++17)
(C++11)
(C++17)
(C++23)
Elementary string conversions
(C++17)
(C++17)
 
 
 
Defined in header <cfloat>
#define FLT_EVAL_METHOD /* implementation defined */
(since C++11)

Specifies the precision in which all floating-point arithmetic operations other than assignment and cast are done.

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

[edit] 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.

[edit] See also

C documentation for FLT_EVAL_METHOD