PLDWWW: DevelopingPLD/AdvancedDeveloping/FixingAsNeeded

[sparky]

Author: sparky   Date: Mon Aug  7 21:51:52 2006 GMT
Module: PLDWWW   URL: http://www.pld-linux.org/DevelopingPLD/AdvancedDeveloping/FixingAsNeeded
---- Log message:


---- Page affected: DevelopingPLD/AdvancedDeveloping/FixingAsNeeded

---- Diffs:

================================================================
  {{{
  $ gcc -l<library> -Wl,--as-needed <objects.o>
  }}}
- library will allways be linked, even if it's not required.
+ library will __allways__ be linked, even if it isn't required.
  
  
  === Short examples ===
  
  Most of problems are with readline/ncurses and tinfo, and it's nice
  example: tinfo is required by both readline and ncurses, and both
- are linked with this library (now, when I've
+ are linked with this library (now, when
- [http://cvs.pld-linux.org/cgi-bin/cvsweb/SOURCES/readline-shared.patch?r1=1.6&r2=1.7 fixed readline]).
+ [http://cvs.pld-linux.org/cgi-bin/cvsweb/SOURCES/readline-shared.patch?r1=1.6&r2=1.7 fixed readline] is fixed).
  
  But some packages link with readline or ncurses while they use __only__
  symbols from tinfo.
  ''Without'' {{{--as-needed}}} those executables work because
  they are linked with tinfo from readline/ncurses library.
- ''With'' {{{--as-needed}}} it will not work, because readline/ncurses
+ ''With'' {{{--as-needed}}} linking will not work, because readline/ncurses
  contain no symbols required by executable
  so they are not linked, it's dependencies naturally are neither linked.
  Thats why there is a need to pass {{{-ltinfo}}}. If it requires only symbols from
@@ -300, +300 @@

  
  And inclorrectly linked one:
  {{{
- $ gcc /usr/lib64/liblftp-jobs.so.0.0.0 
+ $ gcc /usr/lib64/liblftp-jobs.so.0.0.0
  /usr/lib64/gcc/x86_64-pld-linux/4.1.2/../../../../lib64/crt1.o: In function `_start':
  (.text+0x20): undefined reference to `main'
  /usr/lib64/liblftp-jobs.so.0.0.0: undefined reference to `StringSet::Remove(int)'