man8/ldconfig.8

   1 .\" Copyright 1999 SuSE GmbH Nuernberg, Germany
   2 .\" Author: Thorsten Kukuk <kukuk@suse.de>
   3 .\"
   4 .\" This program is free software; you can redistribute it and/or
   5 .\" modify it under the terms of the GNU General Public License as
   6 .\" published by the Free Software Foundation; either version 2 of the
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   9 .\" This program is distributed in the hope that it will be useful,
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  11 .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 .\" General Public License for more details.
  13 .\"
  14 .\" You should have received a copy of the GNU General Public
  15 .\" License along with this manual; if not, see
  16 .\" <http://www.gnu.org/licenses/>.
  17 .\"
  18 .\" Modified, 6 May 2002, Michael Kerrisk, <mtk.manpages@gmail.com>
  19 .\"   Change listed order of /usr/lib and /lib
  20 .TH LDCONFIG 8 2012-05-10 "GNU" "Linux Programmer's Manual"
  21 .SH NAME
  22 ldconfig \- configure dynamic linker run-time bindings
  23 .SH SYNOPSIS
  24 .B /sbin/ldconfig
  25 [
  26 .B \-nNvXV
  27 ]
  28 [
  29 .BR \-f\ conf
  30 ]
  31 [
  32 .BR \-C\ cache
  33 ]
  34 [
  35 .BR \-r\ root
  36 ]
  37 .IR directory \ ...
  38 .PD 0
  39 .PP
  40 .PD
  41 .B /sbin/ldconfig
  42 .B \-l
  43 [
  44 .B \-v
  45 ]
  46 .IR library \ ...
  47 .PD 0
  48 .PP
  49 .PD
  50 .B /sbin/ldconfig
  51 .B \-p
  52 .SH DESCRIPTION
  53 .B ldconfig
  54 creates the necessary links and cache to the most recent shared
  55 libraries found in the directories specified on the command line,
  56 in the file
  57 .IR /etc/ld.so.conf ,
  58 and in the trusted directories
  59 .RI ( /lib
  60 and
  61 .IR /usr/lib ).
  62 The cache is used by the run-time linker,
  63 .I ld.so
  64 or
  65 .IR ld-linux.so .
  66 .B ldconfig
  67 checks the header and filenames of the libraries it encounters when
  68 determining which versions should have their links updated.
  69 .PP
  70 .B ldconfig
  71 will attempt to deduce the type of ELF libs (i.e., libc5 or libc6/glibc)
  72 based on what C libs, if any, the library was linked against.
  73 .\" The following sentence looks suspect
  74 .\" (perhaps historical cruft) -- MTK, Jul 2005
  75 .\" Therefore, when making dynamic libraries,
  76 .\" it is wise to explicitly link against libc (use \-lc).
  77 .PP
  78 Some existing libs do not contain enough information to allow the deduction of
  79 their type.
  80 Therefore, the
  81 .I /etc/ld.so.conf
  82 file format allows the specification of an expected type.
  83 This is
  84 .I only
  85 used for those ELF libs which we can not work out.
  86 The format
  87 is "dirname=TYPE", where TYPE can be libc4, libc5, or libc6.
  88 (This syntax also works on the command line.)
  89 Spaces are
  90 .I not
  91 allowed.
  92 Also see the
  93 .B \-p
  94 option.
  95 .B ldconfig
  96 should normally be run by the superuser as it may require write
  97 permission on some root owned directories and files.
  98 .SH OPTIONS
  99 .TP
 100 .B \-v
 101 Verbose mode.
 102 Print current version number, the name of each directory as it
 103 is scanned, and any links that are created.
 104 Overrides quiet mode.
 105 .TP
 106 .B \-n
 107 Only process directories specified on the command line.
 108 Don't process the trusted directories
 109 .RI ( /lib
 110 and
 111 .IR /usr/lib )
 112 nor those specified in
 113 .IR /etc/ld.so.conf .
 114 Implies
 115 .BR \-N .
 116 .TP
 117 .B \-N
 118 Don't rebuild the cache.
 119 Unless
 120 .B \-X
 121 is also specified, links are still updated.
 122 .TP
 123 .B \-X
 124 Don't update links.
 125 Unless
 126 .B \-N
 127 is also specified, the cache is still rebuilt.
 128 .TP
 129 .B \-f conf
 130 Use
 131 .B conf
 132 instead of
 133 .IR /etc/ld.so.conf .
 134 .TP
 135 .B \-C cache
 136 Use
 137 .B cache
 138 instead of
 139 .IR /etc/ld.so.cache .
 140 .TP
 141 .B \-r root
 142 Change to and use
 143 .I root
 144 as the root directory.
 145 .TP
 146 .B \-l
 147 Library mode.
 148 Manually link individual libraries.
 149 Intended for use by experts only.
 150 .TP
 151 .B \-p
 152 Print the lists of directories and candidate libraries stored in
 153 the current cache.
 154 .SH FILES
 155 .PD 0
 156 .TP 20
 157 .I /lib/ld.so
 158 run-time linker/loader
 159 .TP 20
 160 .I /etc/ld.so.conf
 161 File containing a list of colon, space, tab, newline, or comma-separated
 162 directories in which to search for libraries.
 163 .TP 20
 164 .I /etc/ld.so.cache
 165 File containing an ordered list of libraries found in the directories
 166 specified in
 167 .IR /etc/ld.so.conf ,
 168 as well as those found in
 169 .I /lib
 170 and
 171 .IR /usr/lib .
 172 .PD
 173 .SH SEE ALSO
 174 .BR ldd (1),
 175 .BR ld.so (8)