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Author sdaoden
Recipients ixokai, nadeem.vawda, ned.deily, neologix, pitrou, sdaoden, skrah, vstinner
Date 2011-04-15.15:20:53
SpamBayes Score 1.9473312e-13
Marked as misclassified No
Message-id <20110415152034.GA384@sherwood.local>
I was able to spend more time on that this afternoon.
'Got an unkillable diff(1) along the way which required me to
force a cold reboot.  Well.

I attach a C version (11277.mmap.c) which i've used for testing.
The file 11277.zsum32.c is a quick-and-dirty C program to
calculate CRC-32 and Adler-32 checksums (i had none for the
latter and maybe you want to test some more, so); it requires zlib.
I also attach 11277.1.diff which updates test/, though
this is rather useless, because that still results in a bus error.

This is the real interesting thing however, because the C version
actually works quite well for the chosen value, and the resulting
files are identical, as zsum32 shows:

    Adler-32 <14b9018b> CRC-32 <c6e340bf> -- test_python_413/@test_413_tmp
    Adler-32 <14b9018b> CRC-32 <c6e340bf> -- c-mmap-testfile

I thought
does the trick because it does it in C (hi, Charles-Francois),
but no.
So what do i come up with?
Nothing.  A quick look into 11277.mmap.c will show you this:

    /* *Final* sizes (string written after lseek(2): "abcd") */
        /* Tested good */
        //0x100000000 - PAGESIZE - 5,
        //0x100000000 - 4,
        //0x100000000 - 3,
        //0x100000000 - 1,
        0x100000000 + PAGESIZE + 4,
        //0x100000000 + PAGESIZE + 5,
        /* Tested bad */
        //0x100000000 + PAGESIZE,
        //0x100000000 + PAGESIZE + 1,
        //0x100000000 + PAGESIZE + 3,

Now i have to go but maybe i can do some more testing tomorrow to
answer the question why fails even though there is
the fsync() and even though the values work in C.
Any comments?
File name Uploaded
11277.1.diff sdaoden, 2011-04-15.15:20:52
11277.mmap.c sdaoden, 2011-04-15.15:20:52
11277.zsum32.c sdaoden, 2011-04-15.15:20:53
Date User Action Args
2011-04-15 15:20:58sdaodensetrecipients: + sdaoden, ixokai, pitrou, vstinner, nadeem.vawda, ned.deily, skrah, neologix
2011-04-15 15:20:54sdaodenlinkissue11277 messages
2011-04-15 15:20:53sdaodencreate