NAME    [Toc]    [Back]

       ld.so/ld-linux.so - dynamic linker/loader

DESCRIPTION    [Toc]    [Back]

       ld.so loads the shared libraries needed by a program, prepares the program
 to run, and then runs it.  Unless  explicitly  specified  via  the
       -static	option to ld during compilation, all Linux programs are incomplete
 and require further linking at run time.

       The necessary shared libraries needed by the program are  searched  for
       in the following order

       o      Using	 the	  environment	  variable     LD_LIBRARY_PATH
	      (LD_AOUT_LIBRARY_PATH for a.out programs).  Except if  the  executable
  is a setuid/setgid binary, in which case it is ignored.

       o      From the cache file /etc/ld.so.cache which contains  a  compiled
	      list  of	candidate  libraries previously found in the augmented
	      library path.

       o      In the default path /usr/lib, and then /lib.

ENVIRONMENT    [Toc]    [Back]

       LD_LIBRARY_PATH
	      A colon-separated list of directories in which to search for ELF
	      libraries  at  execution-time.   Similar to the PATH environment
	      variable.

       LD_PRELOAD    [Toc]    [Back]
	      A whitespace-separated list of additional,  user-specified,  ELF
	      shared  libraries  to  be loaded before all others.  This can be
	      used  to	selectively  override  functions   in	other	shared
	      libraries.   For	setuid/setgid  ELF binaries, only libraries in
	      the standard search directories that are	also  setgid  will  be
	      loaded.

       LD_TRACE_LOADED_OBJECTS    [Toc]    [Back]
	      If  present,  causes  the  program  to  list its dynamic library
	      dependencies, as if run by ldd, instead of running normally.

       LD_BIND_NOW    [Toc]    [Back]
	      If present, causes the dynamic linker to resolve all symbols  at
	      program startup instead of when they are first referenced.

       LD_AOUT_LIBRARY_PATH    [Toc]    [Back]
	      A  colon-separated  list	of  directories in which to search for
	      a.out libraries at execution-time.  Similar to the PATH environment
 variable.

       LD_AOUT_PRELOAD    [Toc]    [Back]
	      The  name of an additional, user-specified, a.out shared library
	      to be loaded after all others.  This can be used to  selectively
	      override functions in other shared libraries.

       LD_NOWARN    [Toc]    [Back]
	      Suppress	warnings about a.out libraries with incompatible minor
	      version numbers.

       LD_KEEPDIR    [Toc]    [Back]
	      Don't ignore the directory in the names of a.out libraries to be
	      loaded.  Use of this option is strongly discouraged.

FILES    [Toc]    [Back]

       /lib/ld.so	   a.out dynamic linker/loader
       /lib/ld-linux.so.*  ELF dynamic linker/loader
       /etc/ld.so.cache    File  containing  a compiled list of directories in
			   which to search for libraries and an  ordered  list
			   of candidate libraries.
       /etc/ld.so.preload  File  containing a whitespace separated list of ELF
			   shared libraries to be loaded before  the  program.
			   libraries   and   an   ordered  list  of  candidate
			   libraries.
       lib*.so* 	   shared libraries

SEE ALSO    [Toc]    [Back]

       ldd(1), ldconfig(8).

BUGS    [Toc]    [Back]

       Currently ld.so has no means of unloading and searching for  compatible
       or newer version of libraries.

       ld.so  functionality  is  only available for executables compiled using
       libc version 4.4.3 or greater.

AUTHORS    [Toc]    [Back]

       David Engel, Eric Youngdale, Peter MacDonald, Hongjiu  Lu,  Linus  Torvalds,
  Lars  Wirzenius	and  Mitch  D'Souza  (not  necessarily in that
       order).



				 14 March 1998			      ld.so(8)