s/\\'/\\(aq/

[thirdparty/man-pages.git] / man2 / uname.2

diff --git a/man2/uname.2 b/man2/uname.2
index 091a227224f0f9ea4063cd6166d1cae381767bb7..116a4eb1657ac4711c7c25b231e8be5d4b0cbcb9 100644 (file)
--- a/man2/uname.2
+++ b/man2/uname.2
@@ -20,7 +20,9 @@
 .\" Formatted or processed versions of this manual, if unaccompanied by
 .\" the source, must acknowledge the copyright and authors of this work.
 .\"
-.TH UNAME 2 2001-12-15 "Linux 2.5.0" "Linux Programmer's Manual"
+.\" 2007-07-05 mtk: Added details on underlying system call interfaces
+.\"
+.TH UNAME 2 2007-07-05 "Linux" "Linux Programmer's Manual"
 .SH NAME
 uname \- get name and information about current kernel
 .SH SYNOPSIS
@@ -35,7 +37,7 @@ The
 .I utsname
 struct is defined in
 .IR <sys/utsname.h> :
-.in +0.5i
+.in +4n
 .nf
 
 struct utsname {
@@ -50,10 +52,10 @@ struct utsname {
 };
 
 .fi
-.in -0.5i
+.in
 The length of the arrays in a
 .I struct utsname
-is unspecified; the fields are terminated by a null byte ('\\0').
+is unspecified; the fields are terminated by a null byte (\(aq\\0\(aq).
 .SH "RETURN VALUE"
 On success, zero is returned.
 On error, \-1 is returned, and
@@ -104,16 +106,17 @@ 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.
+.B SYS_NMLN
+or
+.B _SYS_NMLN
+or
+.B UTSLEN
+or
+.BR _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.
 .LP
-There have been three Linux system calls \fIuname\fP().
-The first one
-used length 9, the second one used 65, the third one also uses 65 but
-adds the \fIdomainname\fP field.
-.LP
 Part of the utsname information is also accessible via
 .BR sysctl (2)
 and via
@@ -122,6 +125,29 @@ and via
 .IR osrelease ,
 .IR version ,
 .IR domainname }.
+.SS Underlying kernel interface
+.LP
+Over time, increases in the size of the
+.I utsuname
+structure have led to three successive versions of
+.BR uname ():
+.IR sys_olduname ()
+(slot
+.IR __NR_oldolduname ),
+.IR sys_uname ()
+(slot
+.IR __NR_olduname ),
+and
+.IR sys_newuname ()
+(slot
+.IR __NR_uname) .
+The first one used length 9 for all fields;
+the second used 65;
+the third also uses 65 but adds the \fIdomainname\fP field.
+The glibc
+.BR uname ()
+wrapper function hides these details from applications,
+invoking the most recent version of the system call provided by the kernel.
 .SH "SEE ALSO"
 .BR uname (1),
 .BR getdomainname (2),