FLT_EVAL_METHOD

 

C

Language

Headers

Type support

Program utilities

Variadic function support

Error handling

Dynamic memory management

Date and time utilities

Strings library

Algorithms

Numerics

Input/output support

Localization support

Atomic operations (C11)

Thread support (C11)

Technical Specifications

 

Type support

size_t

ptrdiff_t

NULL

max_align_t (since C11)

offsetof

Numeric limits

 

Numeric limits

FLT_ROUNDS

FLT_EVAL_METHOD (C99)

 

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.