"exit(1);" considered useless; p - (nf)

[Jay Lepreau]

Exactly this (a user-modifiable printf format table of functions) was
actually done long ago by Alan Snyder, then of MIT, now of HP, in his
runtime support for his PDP-10 C compiler.  I currently use most of it
in the printf used in my PDP-10 pcc port.  It works fine.