gethostname(2)gethostname(2)NAMEgethostname() - get name of current host system
returns in the array to which hostname points, the standard host name
for the current system as set by (see sethostname(2)). size specifies
the length of the hostname array. hostname is null-terminated unless
insufficient space is provided.
returns 0 if successful. Otherwise, it returns −1 and sets to indicate
can fail if the following is true:
hostname points to an illegal address. The reliable detection of
this error is implementation dependent.
size is less than one.
It is recommended that programs use to dynamically size the buffer used
to accept the host name from This is preferred over use of the con‐
For cases where the constant must be used, there are two values: 64 and
256. The smaller value is compatible with current releases and is used
by default. To use the larger value consult the related documentation
The administrator may, with appropriate configuration options enabled,
set a host name larger than 64 bytes. Existing applications which were
compiled using the smaller to size a buffer passed to the system func‐
tion obtain only the first 64 bytes. This truncation may cause the
applications to exhibit anomalous behavior or to fail.
was developed by the University of California, Berkeley.
SEE ALSOhostname(1), uname(1), sethostname(2), uname(2), nodehostnamesize(5).