summaryrefslogtreecommitdiff
path: root/ldso/man/ld.so.texi
diff options
context:
space:
mode:
authorWaldemar Brodkorb <wbx@openadk.org>2017-06-11 23:08:10 +0200
committerWaldemar Brodkorb <wbx@openadk.org>2017-06-11 23:08:10 +0200
commitff8e1ce2a6fe6ed135ea0444ce048668a8890b3e (patch)
treee6328904d00cafd495c1bb2e8ee5b4f1163aeca6 /ldso/man/ld.so.texi
parent197a82dd6d478b98cfe499b31cf6e2cfde682314 (diff)
remove outdated manpages and README's for ld.so/linuxthreads
Diffstat (limited to 'ldso/man/ld.so.texi')
-rw-r--r--ldso/man/ld.so.texi411
1 files changed, 0 insertions, 411 deletions
diff --git a/ldso/man/ld.so.texi b/ldso/man/ld.so.texi
deleted file mode 100644
index 4e5fb841b..000000000
--- a/ldso/man/ld.so.texi
+++ /dev/null
@@ -1,411 +0,0 @@
-\input texinfo @c -*-texinfo-*-
-@c %**start of header
-@setfilename ld.so.info
-@settitle ld.so : Dynamic-Link Library support
-@c %**end of header
-
-@ifinfo
-This file documents the dynamic-link support libraries and utilities for the
-Linux OS, version 1.8.1.
-
-Copyright 1996 Michael Deutschmann
-
-This document is subject to the GNU General Public License as published by
-the Free Software foundation, version 2 or later (your choice).
-
-Note: The software described in this document is under a different copyright
-and license.
-
-@end ifinfo
-
-@titlepage
-@title ld.so
-@subtitle Dynamic Link library support for the Linux OS.
-@author David Engel
-@author Eric Youngdale
-@author Peter Macdonald
-@author Hongjiu Lu
-@author Mitch D'Souza
-@author Michael Deutschmann (this documentation)
-
-@page
-Copyright @copyright{} 1996 Michael Deutschmann
-
-This document is subject to the GNU General Public License as published by
-the Free Software foundation, version 2 or later (your choice).
-
-Note: The software described in this document is under a different copyright
-and license.
-@end titlepage
-
-@ifinfo
-@node Top
-@top
-
-The @code{ld.so} module provides dynamic linked library support in Linux.
-This file documents @code{ld.so} and its companion software.
-
-@menu
-* intro:: Introduction
-
-* ld.so:: The dynamic linker core program
-* ldd:: A utility to print out dependencies
-* ldconfig:: A utility to maintain the cache and symlinks
-* libdl:: Manual dynamic linking library
-@end menu
-
-@end ifinfo
-
-@node intro
-@unnumbered Introduction
-
-The @code{ld.so} suite contains special files and utilities needed for linux
-to handle @dfn{dynamic libraries}.
-
-Ordinary static libraries (@file{lib*.a} files) are included into executables
-that use their functions. A file that only uses static libraries needs less
-intelligence to load, but takes up more space. If many executables use the
-same library, there can be much wastage of storage space, since multiple
-copies of the library functions are scattered across the executables.
-However, static libraries are easier to make.
-
-Dynamic libraries (@file{lib*.so*} files) are not copied into executables ---
-the executable is written in such a way that it will automatically load the
-libraries. In linux, the executable will first load the special library
-@code{ld.so} or @code{ld-linux.so}, which contains the intelligence
-to load further dynamic libraries. Since multiple files end up getting
-executable data from the same file, dynamic libraries are also known as
-shared libraries.
-
-Linux executables come in two flavors, @sc{elf} and a.out.
-
-a.out is the original executable format used by Linux. It has somewhat less
-overhead than @sc{elf}. However creating shared libraries for a.out is
-@emph{very} involved, and each a.out shared library must be explicitly
-registered.
-
-@sc{elf} is a more recent format, which supports a much simpler method of
-creating libraries. @sc{elf} libraries may also be linked manually
-(@pxref{libdl}).
-
-Since many library authors prefer @sc{elf} and no longer release shared a.out
-libraries, a.out is moribund on Linux. This version of the @code{ld.so} can
-be compiled to support only @sc{elf}, or to support both formats. (The last
-release of ld.so to support a.out alone was 1.8.0.)
-
-@node ld.so
-@chapter @code{ld.so}: Dynamic linker core
-
-@code{ld.so} works behind the scenes to handle dynamic libraries in Linux.
-Users will almost never have to deal with it directly, but in special cases
-one can send instructions to it through environment variables. Also, if
-something is wrong with your libraries (usually an incorrect version) ld.so
-will give error messages.
-
-Actually @code{ld.so} is the a.out linker. The new @sc{elf} executables are
-handled by a related program @code{ld-linux.so}.
-
-@menu
-* files:: Configuration files used by the suite
-* environment:: Environment settings that tweak @code{ld.so}
-* errors:: Complaints @code{ld.so} might make
-@end menu
-
-@node files
-@section Configuration Files
-
-@table @file
-@item /etc/ld.so.cache
-A file created by @code{ldconfig} and used to speed linking. It's structure
-is private to the suite.
-
-@item /etc/ld.so.conf
-A simple list of directories to scan for libraries, in addition to
-@file{/usr/lib} and @file{/lib}, which are hardwired. It may contain
-comments started with a @samp{#}.
-
-@item /etc/ld.so.preload
-A list of libraries to preload. This allows preloading libraries for
-setuid/setgid executables securely. It may contain comments.
-@end table
-
-@node environment
-@section Environment Variables
-
-@table @code
-@item LD_AOUT_LIBRARY_PATH
-@itemx LD_LIBRARY_PATH
-These variables supply a library path for finding dynamic libraries, in the
-standard colon seperated format. These variables are ignored when executing
-setuid/setgid programs, because otherwise they would be a security hazard.
-@code{ld.so} will use @code{LD_AOUT_LIBRARY_PATH} and @code{ld-linux.so} will
-use @code{LD_LIBRARY_PATH}.
-
-@item LD_AOUT_PRELOAD
-@itemx LD_PRELOAD
-These variables allow an extra library not specified in the executable to be
-loaded. Generally this is only useful if you want to override a function.
-These are also ignored when running setuid/setgid executables. @code{ld.so}
-will use @code{LD_AOUT_PRELOAD} and @code{ld-linux.so} will use
-@code{LD_PRELOAD}.
-
-@item LD_NOWARN
-If non-empty, errors about incompatible minor revisions are suppressed.
-
-@item LD_KEEPDIR
-If non-empty, allow executables to specify absolute library names. This
-option is deprecated.
-@c FIXME:
-@c The following are things I noticed in the ld-linux.so source.
-@c I don't really understand 'em. Could someone help me?
-@c
-@c @item LD_BIND_NOW
-@c This option is used by the @code{ld-linux.so} only. I don't know
-@c what it does. (I suspect, looking at the code, that it specifies
-@c "RTLD_NOW" rather than "RTLD_LAZY" mode for the shared libraries.)
-@c
-@c @item LD_TRACE_LOADED_OBJECTS
-@c @itemx LD_WARN
-@c These seem to have something to do with the communication between the
-@c @code{ld-linux.so} and @code{ldd}. I don't know more.
-@end table
-
-@node errors
-@section Errors
-
-@table @samp
-@item Can't find library @var{library}
-The executable required a dynamically linked library that ld.so cannot find.
-Your symbolic links may be not set right, or you may have not installed a
-library needed by the program.
-
-@item Can't load library @var{library}
-The library is corrupt.
-
-@item Incompatible library @var{library}
-@itemx Require major version @var{x} and found @var{y}
-Your version of the library is incompatible with the executable. Recompiling
-the executable, or upgrading the library will fix the problem.
-
-@item using incompatible library @var{library}
-@itemx Desire minor version >= @var{x} and found @var{y}.
-Your version of the library is older than that expected by the executable,
-but not so old that the library interface has radically changed, so the
-linker will attempt to run anyway. There is a chance that it will work, but
-you should upgrade the library or recompile the software. The environment
-variable @code{LD_NOWARN} can be used to supress this message.
-
-@item too many directories in library path
-The linker only supports up to 32 library directories. You have too many.
-
-@item dynamic linker error in @var{blah}
-The linker is having trouble handling a binary - it is probably corrupt.
-
-@item can't map cache file @var{cache-file}
-@itemx cache file @var{cache-file} @var{blah}
-The linker cache file (generally @file{/etc/ld.so.cache}) is corrupt or
-non-existent. These errors can be ignored, and can be prevented by
-regenerating the cache file with @code{ldconfig}.
-@end table
-
-@node ldd
-@chapter @code{ldd}: Dependency scanner
-
-@code{ldd} is a utility that prints out the dynamic libraries that an
-executable is linked to.
-
-Actually @code{ldd} works by signalling ld.so to print the dependencies.
-For a.out executables this is done by starting the executable with
-@code{argc} equal to 0. The linker detects this and prints the dependencies.
-(This can cause problems with @emph{very} old binaries, which would run as
-normal only with an inappropriate @code{argc}.)
-
-For @sc{elf} executables, special environment variables are used to tell the
-linker to print the dependencies.
-
-@code{ldd} has a few options:
-
-@table @samp
-@item -v
-Print the version number of @code{ldd} itself
-
-@item -V
-Print the version number of the dynamic linker
-
-@item -d
-Report missing functions. This is only supported for @sc{elf} executables.
-
-@item -r
-Report missing objects. This is also only available for @sc{elf}
-executables.
-@end table
-
-@node ldconfig
-@chapter @code{ldconfig}: Setup program
-
-This utility is used by the system administrator to automatically set up
-symbolic links needed by the libraries, and also to set up the cache file.
-
-@code{ldconfig} is run after new dynamic libraries are installed, and if the
-cache file or links are damaged. It is also run when upgrading the
-@code{ld.so} suite itself.
-
-The @file{/lib} and @file{/usr/lib} directories, and any listed in the file
-@file{/etc/ld.so.conf} are scanned by default unless @samp{-n} is used.
-Additional directories may be specified on the command line.
-
-It has the following options:
-
-@table @samp
-@item -D
-Enter debug mode. Implies @samp{-N} and @samp{-X}.
-
-@item -v
-Verbose. Print out links created and directories scanned.
-
-@item -n
-Check directories specified on the commandline @emph{only}.
-
-@item -N
-Do not regenerate the cache.
-
-@item -X
-Do not rebuild symbolic links.
-
-@item -l
-Set up symbolic links for only libraries presented on the command line.
-
-@item -p
-Print out the library pathnames in the cache file (@file{/etc/ld.so.cache})
-@end table
-
-@node libdl
-@chapter User dynamic linking library
-
-The @code{ld.so} package includes a small library of functions
-(@code{libdl}) to allow manual dynamic linking. Normally programs are linked
-so that dynamic functions and objects are automagically available. These
-functions allow one to manually load and access a symbol from a library.
-They are only available for @sc{elf} executables.
-
-@menu
-* using libdl:: General points
-* functions:: How to use the functions
-* example:: A sample program
-@end menu
-
-@node using libdl
-@section Overview
-
-To access this library, add the flag @samp{-ldl} to your compile command when
-linking the executable. You also must include the header file
-@code{dlfcn.h}. You may also need the flag @samp{-rdynamic}, which enables
-resolving references in the loaded libraries against your executable.
-
-Generally, you will first use @code{dlopen} to open a library. Then you use
-@code{dlsym} one or more times to access symbols. Finally you use
-@code{dlclose} to close the library.
-
-These facilities are most useful for language interpreters that provide
-access to external libraries. Without @code{libdl}, it would be neccessary
-to link the interpreter executable with any and all external libraries
-needed by the programs it runs. With @code{libdl}, the interpreter only
-needs to be linked with the libraries it uses itself, and can dynamically
-load in additional ones if programs need it.
-
-@node functions
-@section Functions
-
-@deftypefun void *dlopen ( const char @var{filename}, int @var{flags} )
-
-This function opens the dynamic library specified by @var{filename}
-and returns an abstract handle, which can be used in subsequent calls to
-@code{dlsym}. The function will respect the @code{LD_ELF_LIBRARY_PATH} and
-@code{LD_LIBRARY_PATH} environment variables.
-
-@end deftypefun
-
-The following flags can be used with @code{dlopen}:
-
-@deftypevr Macro int RTLD_LAZY
-Resolve symbols in the library as they are needed.
-@end deftypevr
-
-@deftypevr Macro int RTLD_NOW
-Resolve all symbols in the library before returning, and fail if not all can
-be resolved. This is mutually exclusive with @code{RTLD_LAZY}.
-@end deftypevr
-
-@deftypevr Macro int RTLD_GLOBAL
-Make symbols in this library available for resolving symbols in other
-libraries loaded with @code{dlopen}.
-@end deftypevr
-
-@deftypefun int dlclose ( void *@var{handle} )
-
-This function releases a library handle.
-
-Note that if a library opened twice, the handle will be the same. However,
-a reference count is used, so you should still close the library as many
-times as you open it.
-
-@end deftypefun
-
-@deftypefun void *dlsym (void *@var{handle},char *@var{symbol-name})
-
-This function looks up the name @var{symbol-name} in the library and returns
-it in the void pointer.
-
-If there is an error, a null pointer will be returned. However, it is
-possible for a valid name in the library to have a null value, so
-@code{dlerror} should be used to check if there was an error.
-
-@end deftypefun
-
-@deftypefun {libdl function} {const char} *dlerror( void )
-
-This function is used to read the error state. It returns a human-readable
-string describing the last error, or null, meaning no error.
-
-The function resets the error value each time it is called, so the result
-should be copied into a variable. If the function is called more than once
-after an error, the second and subsequent calls will return null.
-
-@end deftypefun
-
-@node example
-@section Example program
-
-Here is an example program that prints the cosine of two by manually linking
-to the math library:
-
-@example
-@c The following was snarfed verbatim from the dlopen.3 man file.
-#include <stdio.h>
-#include <dlfcn.h>
-
-int main(int argc, char **argv) @{
- void *handle;
- double (*cosine)(double);
- char *error;
-
- handle = dlopen ("/lib/libm.so", RTLD_LAZY);
- if (!handle) @{
- fputs (dlerror(), stderr);
- exit(1);
- @}
-
- cosine = dlsym(handle, "cos");
- if ((error = dlerror()) != NULL) @{
- fputs(error, stderr);
- exit(1);
- @}
-
- printf ("%f\\n", (*cosine)(2.0));
- dlclose(handle);
-@}
-@end example
-
-@contents
-
-@bye