uname.2 (2011 09)

uname(2) uname(2)

RETURN VALUE

uname() and setuname() return the following values:

n Successful completion. n is a nonnegative value.

-1 Failure.

errno is set to indicate the error.

The

uname() function may return truncated results when the non-expanded version of the

utsname

structure is used. See WARNINGS .

ERRORS

uname() or setuname() fails, errno is set to one of the following values.

[EFAULT] name points to an illegal address. The reliable detection of this error is implementa-

tion dependent.

[EPERM]

setuname() was attempted by a process lacking appropriate privileges.

[EOVERFLOW] This error may be detected and indicates that the

utsname structure version used

does not accommodate the full values of one or more ﬁelds.

WARNINGS

uname() returns one of two versions of the

utsname structure:

• HP-UX compatible version (compatible with all HP-UX versions)

• Expanded version of the structure which can accommodate larger values.

The compatible structure is used by default. To use the expanded structure, see nodehostnamesize(5).

If the administrator has conﬁgured a node name with a length larger than 8 bytes, the compatible version

of the

utsname structure, as returned by uname(), contains just the ﬁrst 8 bytes (plus null) in the

utsname.nodename ﬁeld. In a future release the ﬁeld will not contain any data bytes if the entire

node name cannot ﬁt.

Setting a node name of more than 8 bytes with

setuname() is only possible with the appropriate

conﬁguration options enabled. It is strongly recommended that all related documentation be completely

understood before setting a larger node name. A node name larger than 8 bytes can cause anomalous

behavior or failure in applications which use the uname command or the uname() system function to

access the name.

It is recommended that, whenever possible, programs use the host name as returned by the

gethost-

name() function rather than the utsname.nodename

ﬁeld. It can be given a sufﬁciently large buffer

to avoid truncation issues. See gethostname (2) for more information.

AUTHOR

uname() was developed by AT&T and HP.