On Mon, Jun 10, 2002 at 02:45:15PM +0200, Ludovic Courtès wrote: > I have a question about how io_read() should work, and I couldn't find the > answer in io.def. From what I've seen in libdiskfs/io-read.c , a diskfs server > is supposed to reallocate a new buffer if the provided buffer is smaller than > the requested amount of data:
This is not a strict requirement. A server can do any of the following: 1. Allocate a new, large enough buffer. 2. Just return fewer data. and a server can even: 3. Return a new buffer although the old one was large enough. > Therefore, I would not expect io_read() to provide a new buffer with the > following code, since the buffer size if the same as the requested amount of > data (*len == size): > > void* d = data; > > size = (size > *len)?(*len):size; > *len = size; > err = io_read (mbox, (data_t*)&data, len, start + offset, size); > assert (data == d); // this assertion should not fail! > > However, the last assertion does sometimes fail. Well, I would not expect it to fail with a canonical diskfs server. It is not a protocol violation, but if it "shouldn't happen" then it might be worth to investigate why it happens anyway. Thanks, Marcus -- `Rhubarb is no Egyptian god.' Debian http://www.debian.org [EMAIL PROTECTED] Marcus Brinkmann GNU http://www.gnu.org [EMAIL PROTECTED] [EMAIL PROTECTED] http://www.marcus-brinkmann.de _______________________________________________ Help-hurd mailing list [EMAIL PROTECTED] http://mail.gnu.org/mailman/listinfo/help-hurd
