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    Subjectmmap specification - was: ... select specification
    On Thu, Oct 07, 2004 at 03:50:31PM +0100, Alan Cox wrote:

    > I'll quote SuSv3 to illustrate the danger of "specifications"
    > "The system shall always zero-fill any partial page at the end of an
    > object. Further, the system shall never write out any modified portions
    > of the last page of an object which are beyond its end. References
    > within the address range starting at pa and continuing for len bytes to
    > whole pages following the end of an object shall result in delivery of a
    > SIGBUS signal."
    > Its a mistake, its not apparent if its actually meant something entirely
    > different or someone forgot a "not", or what is going on.

    What precisely are you thinking of?
    You seem to think this is ridiculous.
    The way I read this, Linux is compliant, I think.

    [I read this as follows: If you mmap a file with MAP_SHARED and modify
    the memory at an address so far beyond EOF that it is not in a page
    containing stuff from the file, then you get a SIGBUS. -- Linux does this.
    Also, that if you modify the memory at an address beyond EOF, then
    the file is not modified. -- Again Linux does this.]

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