If you memory map a file using mmap(), but then the underlying file changes to a much smaller size. What happens if you access a memory offset that was shaved off from the file?
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If you memory map a file using mmap(), but then the underlying file changes to a much smaller size. What happens if you access a memory offset that was shaved off from the file?
IBM says it is undefined http://publib.boulder.ibm.com/infocenter/iseries/v5r3/index.jsp?topic=%2Fapis%2Fmmap.htm
The same is said in SingleUnixSpecification: http://pubs.opengroup.org/onlinepubs/7908799/xsh/mmap.html
‘undefined’ or ‘unspecified’ means – the OS is allowed to start formatting of disk or anything. Most probable is SIGSEGV-killing your application.