[Gnumed-devel] write access connections

[Horst Herb]

I have just modified gmPG to allow for write access as discussed. The changes 
are still widely uncommented.

For read-only queries, nothing has changed - everything works as before 
without any changes needed. 

For writeable queries, a connection has to be requested with optional 
parameter "readonly" set to zero. The user name is then mangled by the 
connecting function ('_' prepended).
Permissions within gnumed have to be set accordingly
(i.e. user 'jsmith' gets read-only access, but user '_jsmith' may write as 
well where applicable).

This is of course done automatically by a post-installation setup script, but 
for now, in order to try it out, you may just set a few permissions manually.

Read-only queries are still executed via the pooled pre-allocated connections.
For write access, a new connection is created for each connection request, and 
then discarded (either manually or automatically via garbage collection)

The asynchronous notification will work via a separate thread using select() 
on the backend socket; I am still working on thread safety and some testing 
before I put the code in CVS.

Horst