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PR 9805

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* ld.texinfo (--allow-shlib-undefined): Correct description of
        default settings and tidy up the rest of the entry.
This commit is contained in:
Nick Clifton 2009-02-04 09:13:22 +00:00
parent cf1061c036
commit 903249d7bc
2 changed files with 30 additions and 11 deletions
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ld/ChangeLog
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@ -1,3 +1,9 @@
2009-02-04 Nick Clifton <nickc@redhat.com>
PR 9805
* ld.texinfo (--allow-shlib-undefined): Correct description of
default settings and tidy up the rest of the entry.
2009-02-04 Alan Modra <amodra@bigpond.net.au>
* emultempl/spuelf.em (spu_after_open): Don't combine .text.ia.*

35
ld/ld.texinfo
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@ -93,7 +93,7 @@ section entitled ``GNU Free Documentation License''.
@vskip 0pt plus 1filll
@c man begin COPYRIGHT
Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001,
2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3
@ -1383,21 +1383,34 @@ first definition will be used.
@kindex --no-allow-shlib-undefined
@item --allow-shlib-undefined
@itemx --no-allow-shlib-undefined
Allows (the default) or disallows undefined symbols in shared libraries.
Allows or disallows undefined symbols in shared libraries.
This switch is similar to @option{--no-undefined} except that it
determines the behaviour when the undefined symbols are in a
shared library rather than a regular object file. It does not affect
how undefined symbols in regular object files are handled.
The reason that @option{--allow-shlib-undefined} is the default is that
the shared library being specified at link time may not be the same as
the one that is available at load time, so the symbols might actually be
resolvable at load time. Plus there are some systems, (eg BeOS) where
undefined symbols in shared libraries is normal. (The kernel patches
them at load time to select which function is most appropriate
for the current architecture. This is used for example to dynamically
select an appropriate memset function). Apparently it is also normal
for HPPA shared libraries to have undefined symbols.
The default behaviour is to report errors for any undefined symbols
referenced in shared libraries if the linker is being used to create
an executable, but to allow them if the linker is being used to create
a shared library.
The reasons for allowing undefined symbol references in shared
libraries specified at link time are that:
@itemize @bullet
@item
A shared library specified at link time may not be the same as the one
that is available at load time, so the symbol might actually be
resolvable at load time.
@item
There are some operating systems, eg BeOS and HPPA, where undefined
symbols in shared libraries are normal.
The BeOS kernel for example patches shared libraries at load time to
select whichever function is most appropriate for the current
architecture. This is used, for example, to dynamically select an
appropriate memset function.
@end itemize
@kindex --no-undefined-version
@item --no-undefined-version