ILOGB(3) NEWLIB ILOGB(3)NAME
1.28 `ilogb', `ilogbf'--get exponent of floating-point number
SYNOPSIS
#include <math.h>
int ilogb(double VAL);
int ilogbf(float VAL);
DESCRIPTION
All nonzero, normal numbers can be described as M * 2**P. `ilogb' and
`ilogbf' examine the argument VAL, and return P. The functions `frexp'
and `frexpf' are similar to `ilogb' and `ilogbf', but also return M.
RETURNS
`ilogb' and `ilogbf' return the power of two used to form the floating-
point argument. If VAL is `0', they return `FP_ILOGB0'. If VAL is
infinite, they return `INT_MAX'. If VAL is NaN, they return `FP_ILOGB‐
NAN'. (`FP_ILOGB0' and `FP_ILOGBNAN' are defined in math.h, but in
turn are defined as INT_MIN or INT_MAX from limits.h. The value of
FP_ILOGB0 may be either INT_MIN or -INT_MAX. The value of FP_ILOGBNAN
may be either INT_MAX or INT_MIN.)
PORTABILITY
C99, POSIX
SEE ALSOilogb is part of the library. The full documentation for is maintained
as a Texinfo manual. If info and are properly installed at your site,
the command
info
will give you access to the complete manual.
NEWLIB April 2010 ILOGB(3)
