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  36         id 1R9N16-00075n-8R; Thu, 29 Sep 2011 16:15:36 -0400\r
  37 Date: Thu, 29 Sep 2011 16:15:36 -0400\r
  38 From: Austin Clements <amdragon@MIT.EDU>\r
  39 To: David Bremner <david@tethera.net>\r
  40 Subject: Re: Concerns regarding some library functions\r
  41 Message-ID: <20110929201536.GF17905@mit.edu>\r
  42 References: <871uv2unfd.fsf@gmail.com> <87fwjhx6p5.fsf@convex-new.cs.unb.ca>\r
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  78 \r
  79 Quoth David Bremner on Sep 29 at  4:59 pm:\r
  80 > On Thu, 29 Sep 2011 10:51:29 -0400, Austin Clements <amdragon@MIT.EDU> wrote:\r
  81 > \r
  82 > > Yes.  We could just deal with that (there aren't *that* many API\r
  83 > > consumers).  For binary compatibility, I suppose we could even use\r
  84 > > symbol versioning.\r
  85 > \r
  86 > I noticed a similar remark in lib/Makefile.local. But I'm not sure how\r
  87 > this work if the interface of a given library function changed.  Can\r
  88 > someone point me to some more explanation? \r
  89 \r
  90 With symbol versioning we'd still provide the old function (presumably\r
  91 re-implemented in terms of the new function).  Both would wind up in\r
  92 the .so and old binaries would still link against the old symbol.  It\r
  93 doesn't help that much once something gets recompiled; assuming the\r
  94 source isn't requesting a specific version of a symbol, it will try to\r
  95 use the latest version.\r
  96 \r
  97 That, however, is about the extent of my knowledge on symbol\r
  98 versioning.  It's possible this simply doesn't work with symbols that\r
  99 don't already have a version; I'm not sure.\r