This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       The inclusion of the nodename member in this structure does not imply that it is  sufficient  information
       for interfacing to communications networks.

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for  Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

       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
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                                   2017                                         UNAME(3POSIX)

       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.

       No errors are defined.

       Thefollowingsectionsareinformative.

       None.

       None.

       uname — get the name of the current system

       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  values  of  the  structure  members  are not constrained to have any relation to the version of this
       volume of POSIX.1‐2017 implemented in the operating system.  An  application  should  instead  depend  on
       _POSIX_VERSION and related constants defined in <unistd.h>.

       This volume of POSIX.1‐2017 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.

       Upon  successful completion, a non-negative value shall be returned.  Otherwise, -1 shall be returned and
       errno set to indicate the error.

       The Base Definitions volume of POSIX.1‐2017, <sys_utsname.h>

       #include <sys/utsname.h>

       int uname(struct utsname *name);