uname (3p) - Linux Manuals
uname: get the name of the current system
PROLOG
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.NAME
uname - get the name of the current system
SYNOPSIS
#include <sys/utsname.h>
int uname(struct utsname *name);
DESCRIPTION
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 <sys/utsname.h>.
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.
RETURN VALUE
Upon successful completion, a non-negative value shall be returned. Otherwise, -1 shall be returned and errno set to indicate the error.
ERRORS
No errors are defined.
The following sections are informative.
EXAMPLES
APPLICATION USAGE
The inclusion of the nodename member in this structure does not imply that it is sufficient information for interfacing to communications networks.
RATIONALE
The values of the structure members are not constrained to have any relation to the version of this volume of IEEE Std 1003.1-2001 implemented in the operating system. An application should instead depend on _POSIX_VERSION and related constants defined in <unistd.h>.
This volume of IEEE Std 1003.1-2001 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 implementations.
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.
FUTURE DIRECTIONS
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. 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.opengroup.org/unix/online.html .