uname_eoverflow.5 (2010 09)

u
uname_eoverflow(5) uname_eoverflow(5)
(Tunable Kernel Parameters)
NAME
uname_eoverflow - causes uname() system function to return [EOVERFLOW] if values do not fit in
fields
VALUES
Failsafe
1 -on
Default
1 -on
Allowed Values
0 -off
1 -on
DESCRIPTION
The
uname_eoverflow
tunable controls whether programs calling the non-expanded version of
uname() will be alerted to the fact that the values did not fit in their corresponding fields. When this
tunable value is 0, the non-expanded version of
uname() will be silent about any truncation of returned
values. When this tunable value is 1, the caller will be alerted to the truncation with a non-zero return
value and
errno set to [EOVERFLOW].
Changing this tunable does not affect the current system values returned by
uname().
In a future version of HP-UX, the
uname() function will return no data when [EOVERFLOW] (or other
errors) are reported. See the uname(2) manpage for information on uname().
Who Is Expected to Change This Tunable?
The system administrator may change this tunable when it is necessary to change program behavior in
respect to errors.
Restrictions on Changing
This tunable is dynamic. Changes are effective for all subsequent calls to the non-expanded version of
uname().
When Should the Value of This Tunable Be Raised?
This tunable may be raised to 1 when applications need to be alerted to the error from
uname().
What are the Side Effects of Raising the Value?
Raising the tunable value to 1 causes the non-expanded version of the uname() system function to
return a non-zero status and the [EOVERFLOW] error if any value cannot fit in its corresponding field of
the non-expanded structure.
When Should the Value of This Tunable Be Lowered?
This tunable should be lowered to 0 when it is necessary to allow applications to proceed with truncated
values. This may be the case where the application aborts due to the error but will tolerate the truncated
values; for example, because the values are not important to its operation.
What are the Side Effects of Lowering the Value?
Lowering the tunable value to 0 causes the non-expanded version of the
uname() system function
silently truncate any values which do not fit in the non-expanded fields. It will not alert the caller with
an error when such truncation occurs.
What Other Tunable Values Should Be Changed at the Same Time?
None.
WARNINGS
Setting this tunable to 0 (off) means that applications will not be alerted to truncated values returned by
the non-expanded
uname() system call. Applications using such truncated values may fail in a non-
deterministic manner.
As of the HP-UX 11i Version 3 initial release, only the node name value returned by
uname() may be
truncated as no other fields returned by that function can take on values which exceed the non-expanded
field sizes. However, later updates and releases may expand other values, and their corresponding non-
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1