[[meta copyright="Copyright © 2007 Free Software Foundation, Inc."]]
[[meta license="Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License, Version 1.2 or
any later version published by the Free Software Foundation; with no Invariant
Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
is included in the section entitled
[[GNU_Free_Documentation_License|/fdl.txt]]."]]

Say you want to try running file system server (*[[translator/ext2fs]]*<!--`[[translator/ext2fs]]`-->,
*[[translator/jfs]]*<!--`[[translator/jfs]]`-->, ...)  against a modified version of *[[libpager]]*<!--`[[libpager]]`--> and
debug the latter one using [[GDB]].

Set the [[translator]] like this:

    $ settrans -fgap ↩
      jfs.img.i ↩
      /usr/bin/env ↩
        LD_LIBRARY_PATH=~tschwinge/tmp/hurd/hurd.ogi/build/libpager ↩
      "`pwd`"/jfs.obj/jfs ↩
      "`pwd`"/jfs.img

Then, when starting GDB, start it like this (or use an equivalent method, of
course):

    $ LD_LIBRARY_PATH=~tschwinge/tmp/hurd/hurd.ogi/build/libpager ↩
      gdb ↩
      ~tschwinge/tmp/jfs/jfs.obj/jfs 15436
    GNU gdb 6.5-debian
    [...]
    Reading symbols from /lib/libdiskfs.so.0.3...Reading symbols from /lib/debug/lib/libdiskfs.so.0.3...done.
    done.
    Loaded symbols for /lib/libdiskfs.so.0.3
    Reading symbols from /devel4/tschwinge/tmp/hurd/hurd.ogi/build/libpager/libpager.so.0.3...done.
    Loaded symbols for /devel4/tschwinge/tmp/hurd/hurd.ogi/build/libpager/libpager.so.0.3
    Reading symbols from /lib/libstore.so.0.3...Reading symbols from /lib/debug/lib/libstore.so.0.3...done.
    done.
    Loaded symbols for /lib/libstore.so.0.3
    [...]
    (gdb) break pager_demuxer
    Breakpoint 1 at 0x105c98d: file ../../libpager/demuxer.c, line 27.
    [...]
    Breakpoint 1, pager_demuxer (inp=0x12bded0, outp=0x12bbec0) at ../../libpager/demuxer.c:27
    27      {
    (gdb) list
    22      /* Demultiplex a single message directed at a pager port; INP is the
    23         message received; fill OUTP with the reply.  */
    24      int
    25      pager_demuxer (mach_msg_header_t *inp,
    [...]

Voilà.