ilogb():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 || _ISOC99_SOURCE; or
cc -std=c99 ilogbf(),
ilogbl():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or
cc -std=c99
DESCRIPTION
These functions return the exponent part of their argument
as a signed integer.
When no error occurs, these functions
are equivalent to the corresponding
logb(3)
functions, cast to
int.
RETURN VALUE
On success, these functions return the exponent of
x,
as a signed integer.
If
x
is zero, then a domain error occurs, and the functions return
FP_ILOGB0.
If
x
is a NaN, then a domain error occurs, and the functions return
FP_ILOGBNAN.
If
x
is negative infinity or positive infinity, then
a domain error occurs, and the functions return
INT_MAX.
ERRORS
See
math_error(7)
for information on how to determine whether an error has occurred
when calling these functions.
The following errors can occur:
Domain error: x is 0 or a NaN
An invalid floating-point exception
(FE_INVALID)
is raised.
These functions do not set
errno
for this case.
Domain error: x is an infinity
These functions do not set
errno
or raise an exception for this case.
This page is part of release 3.14 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
