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Diffstat (limited to 'upstream/opensuse-leap-15-6/man3/gethostid.3')
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diff --git a/upstream/opensuse-leap-15-6/man3/gethostid.3 b/upstream/opensuse-leap-15-6/man3/gethostid.3 new file mode 100644 index 00000000..e18b18bf --- /dev/null +++ b/upstream/opensuse-leap-15-6/man3/gethostid.3 @@ -0,0 +1,146 @@ +'\" t +.\" Copyright 1993 Rickard E. Faith (faith@cs.unc.edu) +.\" +.\" Updated with additions from Mitchum DSouza <m.dsouza@mrc-apu.cam.ac.uk> +.\" Portions Copyright 1993 Mitchum DSouza <m.dsouza@mrc-apu.cam.ac.uk> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" Modified Tue Oct 22 00:22:35 EDT 1996 by Eric S. Raymond <esr@thyrsus.com> +.TH gethostid 3 2023-03-30 "Linux man-pages 6.04" +.SH NAME +gethostid, sethostid \- get or set the unique identifier of the current host +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <unistd.h> +.PP +.B long gethostid(void); +.BI "int sethostid(long " hostid ); +.fi +.PP +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.PP +.BR gethostid (): +.nf + Since glibc 2.20: + _DEFAULT_SOURCE || _XOPEN_SOURCE >= 500 +.\" || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED + Up to and including glibc 2.19: + _BSD_SOURCE || _XOPEN_SOURCE >= 500 +.\" || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED +.fi +.PP +.BR sethostid (): +.nf + Since glibc 2.21: +.\" commit 266865c0e7b79d4196e2cc393693463f03c90bd8 + _DEFAULT_SOURCE + In glibc 2.19 and 2.20: + _DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500) + Up to and including glibc 2.19: + _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500) +.fi +.SH DESCRIPTION +.BR gethostid () +and +.BR sethostid () +respectively get or set a unique 32-bit identifier for the current machine. +The 32-bit identifier was intended to be unique among all UNIX systems in +existence. +This normally resembles the Internet address for the local +machine, as returned by +.BR gethostbyname (3), +and thus usually never needs to be set. +.PP +The +.BR sethostid () +call is restricted to the superuser. +.SH RETURN VALUE +.BR gethostid () +returns the 32-bit identifier for the current host as set by +.BR sethostid (). +.PP +On success, +.BR sethostid () +returns 0; on error, \-1 is returned, and +.I errno +is set to indicate the error. +.SH ERRORS +.BR sethostid () +can fail with the following errors: +.TP +.B EACCES +The caller did not have permission to write to the file used +to store the host ID. +.TP +.B EPERM +The calling process's effective user or group ID is not the same +as its corresponding real ID. +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.ad l +.nh +.TS +allbox; +lb lb lbx +l l l. +Interface Attribute Value +T{ +.BR gethostid () +T} Thread safety T{ +MT-Safe hostid env locale +T} +T{ +.BR sethostid () +T} Thread safety T{ +MT-Unsafe const:hostid +T} +.TE +.hy +.ad +.sp 1 +.SH VERSIONS +In the glibc implementation, the +.I hostid +is stored in the file +.IR /etc/hostid . +(Before glibc 2.2, the file +.I /var/adm/hostid +was used.) +.\" libc5 used /etc/hostid; libc4 didn't have these functions +.PP +In the glibc implementation, if +.BR gethostid () +cannot open the file containing the host ID, +then it obtains the hostname using +.BR gethostname (2), +passes that hostname to +.BR gethostbyname_r (3) +in order to obtain the host's IPv4 address, +and returns a value obtained by bit-twiddling the IPv4 address. +(This value may not be unique.) +.SH STANDARDS +.TP +.BR gethostid () +POSIX.1-2008. +.TP +.BR sethostid () +None. +.SH HISTORY +4.2BSD; dropped in 4.4BSD. +SVr4 and POSIX.1-2001 include +.BR gethostid () +but not +.BR sethostid (). +.SH BUGS +It is impossible to ensure that the identifier is globally unique. +.SH SEE ALSO +.BR hostid (1), +.BR gethostbyname (3) |