GDB 6.0 and FreeBSD threads

Julian Elischer julian at elischer.org
Sun Mar 28 21:15:02 PST 2004


Niall Douglas wrote:
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> On 28 Mar 2004 at 9:47, Daniel Eischen wrote:
> 
> 
>>No-one has touched uthread support for other GDB's as
>>far as I know.  Most work is going in to our other thread
>>libraries.  There is work trying to get GDB thread support
>>for libpthread, and that should be here by 5.3-release.
> 
> 
> I discovered late last night that libc_r implements only userland 
> threads which seem to have issues with pipes (my code kept hanging 
> inside the pipe i/o). I then discovered there are real system scope 
> threads too, but they're in a different library called libkse.

actually it's now called libpthread and linkse was it's development name.
We have't been exactly quiet about this.. it's even in the release notes for 5.2.1.

> 
> You guys could seriously improve the documentation inside the man 
> pages. Please! Just a two line paragraph would have saved me more 
> than a day of work.
> 

we can't guess what question every developer is going to ask..
But possibly the following paragraph in "man pthread"
might be made a bit clearer...


INSTALLATION
      The current FreeBSD POSIX thread implementation is built in three
      libraries, Reentrant C Library (libc_r, -lc_r), POSIX Threads Library
      (libpthread, -lpthread), and 1:1 Threading Library (libthr, -lthr).  They
      contain both thread-safe versions of Standard C Library (libc, -lc) func-
      tions and the thread functions.  Threaded applications are linked with
      one of these libraries.



> After linking to libkse and finding it really doesn't like coexisting 
> with libc_r, I discovered the libmap.conf trick and it works now. 
> Unfortunately I'm back to square one in that no gdb supports kse 
> threads. This is a major problem as my code is heavily multithreaded.

why is libc_r beinbg linked into your application?
you need to select ONE of the libraries and link with that..

> 
> Does this David Xu have some patch code for gdb around in some CVS 
> repository? The only thing stopping me moving to FreeBSD as my 
> primary Unix development platform is this as it's significantly 
> faster than RedHat 9 on my system. If I could grab this support and 
> get it mostly working, I could move to BSD permanently (in these last 
> three days I find I prefer it to Linux for some unknown reason).


The threads support package is at:

http://people.freebsd.org/~davidxu/kse/thread_db/
however, realise that this is PRE_ALPHA.
you are "on your own" except for direct corespondence with david.


> 
> Cheers,
> Niall
> 
> 
> 
> 
> 
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