From owner-freebsd-hackers  Thu May 18  8:55: 7 2000
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Date: Thu, 18 May 2000 11:55:09 -0400
From: Joy Ganguly <joy@niksun.com>
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Subject: Re: Question about file write????
References: <20000517160746.12768.qmail@www0a.netaddress.usa.net> <20000517102516.B14968@fw.wintelcom.net> <3922DB0F.9D9095C9@falcon.niksun.com> <20000517135644.D14968@fw.wintelcom.net> <39231E06.31DFB153@falcon.niksun.com> <200005172324.QAA28046@apollo.backplane.com>
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Matthew Dillon wrote:

>
>     I think it would be a whole lot easier to implement mmap() on the
>     device, then allow the user process to mmap() the device buffer
>     and read() and write() it directly.  I don't think you need to
>     implement any ioctl's for this problem.
>
>     fd = open device
>     ptr = mmap(...)
>
>     fd = open file
>     read(fd, ptr, BUFSIZE)              read from file, store into device buf
>     ...
>     write(fd, ptr, BUFSIZE)             read from device buf, store into file
>
>

I am sorry that i missed this point in my previous post. well the
problem with
the mmap is that my device does not have a buffer always. earlier the
'read'
ioctl on the device used to sleep till a buffer was available. what does
the
mmap do?? can it block?? i am sorry if this sounds naive bcoz i am a
relative
newbie

thanx in advance

-joy


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