_doprnt and _flsbuf

[Michael Zehr]

(i posed this question locally a few weeks ago but got no response, so
i'm trying again with wider distribution)

i'm trying to port some software from unix to vms operating system.  the
software redefines some standard functions, and makes use of
non-standard macros.  in particular _flsbuf and _doprnt.  on this
system, _flsbuf is referenced in <stdio.h> in putc, but i can't find the
definition for it anywhere.  

i can guess what the definition for each of these is by their context,
but if anyone has the actual definitions, i'd appreciate them just in
case they do something unexpected.

thankx in advance,
michael j zehr