Large File Tests fail with Visual Studio 2015

[WardF]

Large File tests are failing under Windows 10 when using Visual Studio 2015 (VS14). I've confirmed this using hdf5 1.8.15 and hdf5 1.8.16 (which shouldn't matter anyways), and have tried with libraries built using VS12 as well as VS14 . Visual Studio 13 (VS12) continues to work as expected.

[WardF]

All tests failing are:

• nc_test4/tst_large2
• nc_test4/tst_large
• nc_tes/tst_big_var
• nc_test/tst_big_rvar
• nc_test/quick_large_files

See http://my.cdash.org/testDetails.php?test=23591494&build=920726 for details regarding one of the failures.

[WardF]

At the initial glance, failures appear to be related to calls to nc_close() and nc_open().

[WardF]

Diving into nc_test4/tst_large2(), I've traced the first error to a non-zero return code in posixio.c:fgrow2(). Specifically, the call to fstat on line 190 is returning 132.

• Reference to MSDN for fstat: https://msdn.microsoft.com/en-us/library/221w8e43.aspx?f=255&MSPPError=-2147217396

[WardF]

When trying to track down errno 132 ,I've found the following:

• http://www.ioplex.com/~miallen/errcmpp.html

This suggests that the problem/error is ENOBUFS, e.g. no buffer space available. odd.

Note that Windows is not listed as one of the platforms on this webpage, however

• https://msdn.microsoft.com/en-us/library/5814770t.aspx suggests that ENOBUFS is maintained for posix compatibility.

This may be a red herring, however; the same page says that we may need to reference _doserrno instead of errno for the "true" error number. More testing needed.

[WardF]

Found a comment in libsrc/posixio.c that I vaguely recall writing (for function ncio_px_filesize);

    /* There is a problem with fstat on Windows based systems
        which manifests (so far) when Config RELEASE is built.
        Use _filelengthi64 isntead. */

This suggests that I've encountered this or a similar issue in the past. It's also possible that we need to be using fstat64 instead of fstat. Diagnosis continues.

[WardF]

I've got a fix in place, but another issue needs investigating. With Large File Tests enabled (-DENABLE_LARGE_FILE_TESTS), the tests under Visual Studio 2015 anecdotally take much longer to complete, compared to the same code (branch gh88) with Visual Studio 2013. I need to do some formal testing of timings, to rule out one-off issues. Once this is established I'll add a comment here and, if necessary, open a new GitHub issue.

[WardF]

The timing issue has not reoccurred so I'm treating it as a one-off for now. The fix is in branch gh188 and will be merged after Travis tests pass.

[WardF]

Fix has been pushed into master.