man8/ldconfig.8

   1 .\" Copyright 1999 SuSE GmbH Nuernberg, Germany
   2 .\" Author: Thorsten Kukuk <kukuk@suse.de>
   3 .\"
   4 .\" %%%LICENSE_START(GPLv2+_SW_3_PARA)
   5 .\" This program is free software; you can redistribute it and/or
   6 .\" modify it under the terms of the GNU General Public License as
   7 .\" published by the Free Software Foundation; either version 2 of the
   8 .\" License, or (at your option) any later version.
   9 .\"
  10 .\" This program is distributed in the hope that it will be useful,
  11 .\" but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 .\" General Public License for more details.
  14 .\"
  15 .\" You should have received a copy of the GNU General Public
  16 .\" License along with this manual; if not, see
  17 .\" <http://www.gnu.org/licenses/>.
  18 .\" %%%LICENSE_END
  19 .\"
  20 .\" Modified, 6 May 2002, Michael Kerrisk, <mtk.manpages@gmail.com>
  21 .\"   Change listed order of /usr/lib and /lib
  22 .TH LDCONFIG 8 2015-03-29 "GNU" "Linux Programmer's Manual"
  23 .SH NAME
  24 ldconfig \- configure dynamic linker run-time bindings
  25 .SH SYNOPSIS
  26 .B /sbin/ldconfig
  27 [
  28 .B \-nNvXV
  29 ]
  30 [
  31 .BR \-f\ conf
  32 ]
  33 [
  34 .BR \-C\ cache
  35 ]
  36 [
  37 .BR \-r\ root
  38 ]
  39 .IR directory \ ...
  40 .PD 0
  41 .PP
  42 .PD
  43 .B /sbin/ldconfig
  44 .B \-l
  45 [
  46 .B \-v
  47 ]
  48 .IR library \ ...
  49 .PD 0
  50 .PP
  51 .PD
  52 .B /sbin/ldconfig
  53 .B \-p
  54 .SH DESCRIPTION
  55 .B ldconfig
  56 creates the necessary links and cache to the most recent shared
  57 libraries found in the directories specified on the command line,
  58 in the file
  59 .IR /etc/ld.so.conf ,
  60 and in the trusted directories,
  61 .I /lib
  62 and
  63 .IR /usr/lib
  64 (on some 64-bit architectures such as x86-64,
  65 .I lib
  66 and
  67 .IR /usr/lib
  68 are the trusted directories for 32-bit libraries, while
  69 .I /lib64
  70 and
  71 .IR /usr/lib64
  72 are used for 64-bit libraries).
  73
  74 The cache is used by the run-time linker,
  75 .I ld.so
  76 or
  77 .IR ld-linux.so .
  78 .B ldconfig
  79 checks the header and filenames of the libraries it encounters when
  80 determining which versions should have their links updated.
  81 .PP
  82 .B ldconfig
  83 will attempt to deduce the type of ELF libraries (i.e., libc5 or libc6/glibc)
  84 based on what C libraries, if any, the library was linked against.
  85 .\" The following sentence looks suspect
  86 .\" (perhaps historical cruft) -- MTK, Jul 2005
  87 .\" Therefore, when making dynamic libraries,
  88 .\" it is wise to explicitly link against libc (use \-lc).
  89 .PP
  90 Some existing libraries do not contain enough information
  91 to allow the deduction of their type.
  92 Therefore, the
  93 .I /etc/ld.so.conf
  94 file format allows the specification of an expected type.
  95 This is used
  96 .I only
  97 for those ELF libraries which we can not work out.
  98 The format
  99 is "dirname=TYPE", where TYPE can be libc4, libc5, or libc6.
 100 (This syntax also works on the command line.)
 101 Spaces are
 102 .I not
 103 allowed.
 104 Also see the
 105 .B \-p
 106 option.
 107 .B ldconfig
 108 should normally be run by the superuser as it may require write
 109 permission on some root owned directories and files.
 110 .SH OPTIONS
 111 .TP
 112 .BR \-c " \fIfmt\fP, " \-\-format=\fIfmt\fP
 113 (Since glibc 2.2)
 114 Cache format to use:
 115 .IR old ,
 116 .IR new ,
 117 or
 118 .IR compat
 119 (default).
 120 .TP
 121 .BI "\-C " cache
 122 Use
 123 .I cache
 124 instead of
 125 .IR /etc/ld.so.cache .
 126 .TP
 127 .BI "\-f " conf
 128 Use
 129 .I conf
 130 instead of
 131 .IR /etc/ld.so.conf .
 132 .\" FIXME glibc 2.7 added -i
 133 .TP
 134 .BR \-i ", " \-\-ignore\-aux\-cache
 135 (Since glibc 2.7)
 136 .\"             commit 27d9ffda17df4d2388687afd12897774fde39bcc
 137 Ignore auxiliary cache file.
 138 .TP
 139 .B \-l
 140 (Since glibc 2.2)
 141 Library mode.
 142 Manually link individual libraries.
 143 Intended for use by experts only.
 144 .TP
 145 .B \-n
 146 Process only the directories specified on the command line.
 147 Don't process the trusted directories,
 148 nor those specified in
 149 .IR /etc/ld.so.conf .
 150 Implies
 151 .BR \-N .
 152 .TP
 153 .B \-N
 154 Don't rebuild the cache.
 155 Unless
 156 .B \-X
 157 is also specified, links are still updated.
 158 .TP
 159 .BR \-p ", " \-\-print\-cache
 160 Print the lists of directories and candidate libraries stored in
 161 the current cache.
 162 .TP
 163 .BI "\-r  " root
 164 Change to and use
 165 .I root
 166 as the root directory.
 167 .TP
 168 .BR \-v ", " \-\-verbose
 169 Verbose mode.
 170 Print current version number, the name of each directory as it
 171 is scanned, and any links that are created.
 172 Overrides quiet mode.
 173 .TP
 174 .BR \-V ", " \-\-version
 175 Print program version.
 176 .TP
 177 .B \-X
 178 Don't update links.
 179 Unless
 180 .B \-N
 181 is also specified, the cache is still rebuilt.
 182 .SH FILES
 183 .\" FIXME Since glibc-2.3.4, "include" directives are supported in ld.so.conf
 184 .\"
 185 .\" FIXME Since glibc-2.4, "hwcap" directives are supported in ld.so.conf
 186 .PD 0
 187 .TP 20
 188 .I /lib/ld.so
 189 Run-time linker/loader.
 190 .TP 20
 191 .I /etc/ld.so.conf
 192 File containing a list of directories, one per line,
 193 in which to search for libraries.
 194 .TP 20
 195 .I /etc/ld.so.cache
 196 File containing an ordered list of libraries found in the directories
 197 specified in
 198 .IR /etc/ld.so.conf ,
 199 as well as those found in the trusted directories.
 200 .PD
 201 .SH SEE ALSO
 202 .BR ldd (1),
 203 .BR ld.so (8)