This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
The uname() function shall store information identifying the current
system in the structure pointed to by name.
The uname() function uses the utsname structure defined in
The uname() function shall return a string naming the current system
in the character array sysname. Similarly, nodename shall contain
the name of this node within an implementation-defined communications
network. The arrays release and version shall further identify the
operating system. The array machine shall contain a name that
identifies the hardware that the system is running on.
The format of each member is implementation-defined.
The values of the structure members are not constrained to have any
relation to the version of this volume of POSIX.1‐2008 implemented in
the operating system. An application should instead depend on
_POSIX_VERSION and related constants defined in <unistd.h>.
This volume of POSIX.1‐2008 does not define the sizes of the members
of the structure and permits them to be of different sizes, although
most implementations define them all to be the same size: eight bytes
plus one byte for the string terminator. That size for nodename is
not enough for use with many networks.
The uname() function originated in System III, System V, and related
implementations, and it does not exist in Version 7 or 4.3 BSD. The
values it returns are set at system compile time in those historical
4.3 BSD has gethostname() and gethostid(), which return a symbolic
name and a numeric value, respectively. There are related
sethostname() and sethostid() functions that are used to set the
values the other two functions return. The former functions are
included in this specification, the latter are not.
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) In the event of any discrepancy between this version and
the original IEEE and The Open Group Standard, the original IEEE and
The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
IEEE/The Open Group 2013 UNAME(3P)