[tor-bugs] #20530 [Core Tor/Tor]: undefined reference to 'munmap' and 'mmap' building tor on Windows

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#20530: undefined reference to 'munmap' and 'mmap' building tor on Windows
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 Reporter:  ice                       |          Owner:
     Type:  defect                    |         Status:  new
 Priority:  Medium                    |      Milestone:  Tor: 0.3.0.x-final
Component:  Core Tor/Tor              |        Version:
 Severity:  Normal                    |     Resolution:
 Keywords:  windows, mingw, backport  |  Actual Points:
Parent ID:                            |         Points:
 Reviewer:                            |        Sponsor:
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Comment (by ice):

 Okay. After more looking into this, it seems that I did have the libmman.a
 in one lib directory, which I suspect is the one picked up by the
 configure script. However, due to the nature of MinGW64 there are now
 several library directories that GCC can access depending on the type of
 build x64, X86, etc. So even though libmman.a was picked up by configure,
 the build system looked for it in MinGW64/x86_64-w64-mingw32/lib directory
 instead of MinGW64/mingw/lib where it is found.

 Alas, building and installing the mman-win32 and installing it in the
 MinGW64/x86_64-w64-mingw32/lib and adding a link to it in the Makefile,
 results in the build succeeding albeit with failed tests related to mmap
 functions. As an aside the tests in the mman-win32 library all pass.

 At any rate, seeing that my vanilla GCC 5.3.0 (still referred to as
 MinGW64) does not contain the mman.h or the libmman.a, I tried hiding the
 mman.h by renaming it in GCC 4.7.3 (which is the one I used here) and
 issuing configure, make, and make test. Sure enough the configure script
 cannot find the header file, the build succeeds and all the tests pass.
 Except those referring to mmap of course are never tested, since they are
 now not available. I enclose the test output for reference. The question
 now is whether the removal of said functionality renders tor unusable, and
 whether or not that functionality exists in the tor distributed by the tor
 project whether in the Expert package or in the torbrowser.

 Thanks

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/20530#comment:7>
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