Re: libtrivfs/glibc questions

[Neal H Walfield]

On Wed, Jan 03, 2001 at 12:51:44AM +0100, Moritz Schulte wrote:
> Hi,
> 
> can anybody please explain me what this 'data_len' parameter in
> trivfs_S_io_read() trans/hello.c is for?
>
> Where does it come from?

How much data is in the array DATA; this does not have to match amount
nor the size of DATA.

> And some more general questions:
> 
> If i have a trivfs translator, who exactly calls (for example)
> libtrivfs_S_io_read()?

The point of the hurd libraries is that they manage the gory details for
you.  Trivfs, along with the rest, manage the root port, i.e. the
translated node.  Thus, when someone tries open the translated node, e.g.
/home/neal/mytranslator, a getroot rpc is generated, Cf.
/include/hurd/fsys.def, and, as the process, i.e. the library, is
listening to the port, the demuxer is invoked with the message which
it dispatches to the appropriate function -- trivfs_S_* among others.
They, in turn, do some processing and calls the user provided hooks.

This is most of it;  I have chosen to gloss over a few details.  As you
ask more questions and begin experimenting, the rest will begin to
reveal itself.

> In the glibc, what does it mean if a function name begins with '__'?

They are private with respect to glibc; do not use them.  All others
are, however, fair game.

-Neal

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