[MacPorts] #41874: Exempi patch causes python ctypes problem, relates to ticket 20965

[MacPorts]

#41874: Exempi patch causes python ctypes problem, relates to ticket 20965
-------------------------------+--------------------------------
 Reporter:  john.g.evans.ne@…  |      Owner:  macports-tickets@…
     Type:  defect             |     Status:  new
 Priority:  Normal             |  Milestone:
Component:  ports              |    Version:  2.2.1
 Keywords:                     |       Port:  exempi
-------------------------------+--------------------------------
 When trying to access the exempi library via python's ctypes module, the
 following error is seen

 {{{
 >>> import ctypes
 >>> c = ctypes.CDLL('/opt/local/lib/libexempi.dylib')
 Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
   File
 "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/ctypes/__init__.py",
 line 365, in __init__
     self._handle = _dlopen(self._name, mode)
 OSError: dlopen(/opt/local/lib/libexempi.dylib, 6): Symbol not found:
 __Z16ConvertToMacLangRKSstPSs
   Referenced from: /opt/local/lib/libexempi.dylib
   Expected in: flat namespace
  in /opt/local/lib/libexempi.dylib
 }}}

 This does not happen when exempi is compiled from source.  The symbol
 being referenced is the `ConvertToMacLang` function, which is defined in
 exempi's `Quicktime_Support.cpp` file, and exempi's portfile excludes this
 file from the library (as applied by the 3rd of three patches)

 {{{
 # see http://trac.macports.org/ticket/20965
 if {${build_arch} eq "x86_64" || ${build_arch} eq "ppc64"} {
     patchfiles-append      patch-
 source__XMPFiles__FormatSupport__Makefile.am
     configure.cppflags-append     -DXMP_64
 }
 }}}

 However, `ConvertToMacLang` is called in another exempi file, so the
 symbol is still there and listed as undefined when `nm` is used on the
 library.

 {{{
 nm /opt/local/lib/libexempi.dylib | grep ConvertToMac
                  U __Z16ConvertToMacLangRKSstPSs

 }}}

 When looking over the history of ticket #20965, it looks to me like the
 original issue that the ticket tries to resolve has actually been resolved
 upstream by the exempi maintainer (see exempi bug #58175 at
 https://bugs.freedesktop.org/show_bug.cgi?id=58175 ).

 When the above portfile stanza is removed and exempi recompiled and
 reinstalled with only the first two patches applied, python can then load
 the library via ctypes.  Have tested this on snow leopard, lion, and
 mavericks.

-- 
Ticket URL: <https://trac.macports.org/ticket/41874>
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