Defined in header
#define FLT_ROUNDS /* implementation defined */
Specifies the current rounding direction of floating-point arithmetic operations.
||the default rounding direction is not known|
||toward zero; same meaning as FE_TOWARDZERO|
||to nearest; same meaning as FE_TONEAREST|
||towards positive infinity; same meaning as FE_UPWARD|
||towards negative infinity; same meaning as FE_DOWNWARD|
|other values||implementation-defined behavior|
The rounding mode can be changed with std::fesetround and FLT_ROUNDS reflects that change.
 See also
| indicates floating-point rounding modes |
| gets or sets rounding direction |
| floating-point rounding direction |
C documentation for FLT_ROUNDS