Re: New port interface

[Gary Houston <ghouston@easynet.co.uk>]

| There is an assumption in this that all ports are fports. For example
| scm_putc will call scm_syserror (via the macro SCM_MAYBE_DRAIN_INPUT) if
| an error happens when the port's seek function is called. This is not
| always appropriate because the error may not be a system error. If it
| isn't then we'll be issuing errors like "Error: Success".
| 
| We need a mechanism in the scm_ptobs interface to allow the underlying
| port implementation to return error messages. Perhaps something as simple
| as another function pointer, which in the case of fports could just call
| strerror(errno).

I think it's OK in the latest version in CVS.  SCM_MAYBE_DRAIN_INPUT
no longer exists and the ptob procedures can throw errors any way they
like.  There was a glitch that meant yesterdays copy was somewhat
out-of-date.