diff options
| -rw-r--r-- | ld/ChangeLog | 6 | ||||
| -rw-r--r-- | ld/ld.texinfo | 35 |
2 files changed, 30 insertions, 11 deletions
diff --git a/ld/ChangeLog b/ld/ChangeLog index 9aa4cb4..b79be39 100644 --- a/ld/ChangeLog +++ b/ld/ChangeLog @@ -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.* diff --git a/ld/ld.texinfo b/ld/ld.texinfo index 49d1743..f38386b 100644 --- a/ld/ld.texinfo +++ b/ld/ld.texinfo @@ -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 |