UNAME(2)		  Linux Programmer's Manual		     UNAME(2)



NAME
       uname - get name and information about current kernel

SYNOPSIS
       #include 

       int uname(struct utsname *buf);

DESCRIPTION
       uname  returns  system information in the structure pointed to by buf.
       The utsname struct is defined in :
	      struct utsname {
		      char sysname[];
		      char nodename[];
		      char release[];
		      char version[];
		      char machine[];
	      #ifdef _GNU_SOURCE
		      char domainname[];
	      #endif
	      };
       The length of the arrays in  a  struct  utsname	is  unspecified;  the
       fields are NUL-terminated.

RETURN VALUE
       On  success, zero is returned.  On error, -1 is returned, and errno is
       set appropriately.

ERRORS
       EFAULT buf is not valid.

CONFORMING TO
       SVr4, SVID, POSIX, X/OPEN.  There is no uname call in BSD 4.3.

       The domainname member (the NIS or YP domain name) is a GNU  extension.

NOTES
       This  is	 a system call, and the operating system presumably knows its
       name, release and version. It also knows what  hardware	it  runs  on.
       So,  four  of  the  fields of the struct are meaningful.	 On the other
       hand, the field nodename is meaningless: it  gives  the	name  of  the
       present	machine in some undefined network, but typically machines are
       in more than one network and have several names. Moreover, the  kernel
       has  no way of knowing about such things, so it has to be told what to
       answer here.  The same holds for the additional domainname field.

       To this end Linux uses the system calls sethostname(2) and  setdomain-
       name(2).	  Note	that there is no standard that says that the hostname
       set by sethostname(2) is the same string as the nodename field of  the
       struct  returned by uname (indeed, some systems allow a 256-byte host-
       name and an 8-byte nodename), but this is  true	on  Linux.  The	 same
       holds for setdomainname(2) and the domainname field.

       The  length of the fields in the struct varies. Some operating systems
       or libraries use a hardcoded 9 or 33 or 65 or 257. Other	 systems  use
       SYS_NMLN	 or  _SYS_NMLN or UTSLEN or _UTSNAME_LENGTH. Clearly, it is a
       bad idea to use any of these constants - just use sizeof(...).	Often
       257 is chosen in order to have room for an internet hostname.

       There  have  been three Linux system calls uname(). The first one used
       length 9, the second one used 65, the third one also uses 65 but	 adds
       the domainname field.

       Part  of the utsname information is also accessible via sysctl and via
       /proc/sys/kernel/{ostype, hostname, osrelease, version, domainname}.

SEE ALSO
       uname(1), getdomainname(2), gethostname(2)



Linux 2.5.0			  2001-12-15			     UNAME(2)