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Installing liboost-dev on Debian Squeeze gives me several libraries like /usr/lib/libboost_thread.so.1.42.0, but no libboost_thread.so. Now I can't link using the -l flag of gcc / ld because the names don't end in .so.

I notice that /usr/lib has plenty of other libraries of the form libfoo.so.N without a libfoo.so, so this isn't peculiar to Boost. I ended up adding libboost_thread.so.1 and libboost_thread.so symlinks links by hand. (The man page for ldconfig suggests it will add the links, but it didn't do anything).

Everything works fine, but it feels dirty. What should I have done?

  • use some more specific linker option I haven't found yet (at the cost of making my makefiles depend on a specific version number).
  • just add the symlinks by hand (at the risk of subverting package management).
  • some other Debian 'right way' to do it.
fizzer
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  • If this question looks familiar, I asked something similar a couple of weeks ago, deleted it as off-topic, changed my mind again, then found out that I need +10k karma to reinstate my own deleted posts. – fizzer May 29 '11 at 15:15

2 Answers2

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You installed the run-time package libboost-thread1.42.0 but the development package libboost-thread-dev (or even the catch-all package libboost-all-dev.

Once you have the corresponding -dev package, linking will work. That is a general feature of most Linux distribution---you almost never want to mess with the symlinks by hand.

Edit: In response to your comment:

edd@max:~$ ls -l /usr/lib/libboost_thread.*
-rw-r--r-- 1 root root 176324 2010-10-21 00:56 /usr/lib/libboost_thread.a
lrwxrwxrwx 1 root root     25 2011-05-14 10:17 /usr/lib/libboost_thread.so -> \
                                                        libboost_thread.so.1.42.0
-rw-r--r-- 1 root root  88824 2010-10-21 00:56 /usr/lib/libboost_thread.so.1.42.0
edd@max:~$ dpkg -S /usr/lib/libboost_thread.so
libboost-thread1.42-dev: /usr/lib/libboost_thread.so
edd@max:~$

Clearly the package management system created the links, and owns them.

Dirk Eddelbuettel
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  • As stated, I installed libboost-dev. 'dpkg --get-selections | grep boost' shows libboost-dev and libboost1.42-dev. Everything is correct (including headers in /usr/include) except the symlinks. – fizzer May 29 '11 at 21:47
  • See my edit to your question -- I'd suggest purging those two packages and reinstalling them. – Dirk Eddelbuettel May 29 '11 at 21:50
  • OK - I installed libboost-all-dev and that put the proper symlinks in. Thank you very much. I guess libboost-dev is broken. – fizzer May 29 '11 at 21:55
  • You know, it may be that libboost-dev is old and that you needed libboost-thread1.42-dev which gets pulled in via libboost-all-dev. The *general rule* of needing the -dev package for the run-time package still holds. Good to know you're up and running now. – Dirk Eddelbuettel May 29 '11 at 22:01
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Dirk's answer is correct about the general principle but there seems to be an extra trap for the unwary with the boost packaging.

Normally the headers and the library symlink are in the same package, so you get the library symlink without thinking about it. However with boost "libboost<version>-dev" provides the headers but "libboost-<lib><version>-dev" provides the shared library symlink. So if you only install the former you get stuff compiling but not linking.

plugwash
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