Visual Studio 6.0

Extracts exponential value of double-precision floating-point argument.

double _logb( double x );

Routine Required Header Compatibility
_logb <float.h> Win 95, Win NT

For additional compatibility information, see Compatibility in the Introduction.


LIBC.LIB Single thread static library, retail version
LIBCMT.LIB Multithread static library, retail version
MSVCRT.LIB Import library for MSVCRT.DLL, retail version

Return Value

_logb returns the unbiased exponential value of x.



Double-precision floating-point value


The _logb function extracts the exponential value of its double-precision floating-point argument x, as though x were represented with infinite range. If the argument x is denormalized, it is treated as if it were normalized.

Floating-Point Support Routines

See Also   frexp