Re: how to write get_block?

[Manfred Spraul]

Manfred Spraul wrote:
> I'll check the POSIX standard, perhaps we can just reject mmap() or
> file-locks in this situation.

I couldn't find it in the POSIX standart, but at least some UNIXes don't
allow it:

http://hoth.stsci.edu/man/man2/fcntl.html: (sun unix)
> The fcntl() function will fail if: [...]
> or the cmd argument is F_SETLK, F_SETLK64, F_SETLKW, or F_SETLKW64,
> mandatory file/record locking is set, and the file is currently
> being mapped to virtual memory using mmap(2). 

http://cando.dwr.co.gov/cgi-bin/man2html/fcntl(2): IRIX 5.2
>  [EAGAIN]       cmd is F_SETLK or F_SETLKW , mandatory file locking bit is
>                     set for the file, and the file is currently being mapped
>                     to virtual memory via mmap [see mmap(2)].