1 Once upon a time Upas ran on many versions of Unix.
2 This is a partial rewrite to ANSI C specifically for Plan 9.
3 It uses's Plan 9's bio library instead of stdio and Plan 9's
4 regular expression library.
6 I've tried to make portability possible but it has
7 never been ported. To port Upas to another system:
9 - port Plan 9's libbio library working on that system (already available).
10 - port Plan 9's regexp library working on that system (should just compile).
11 - rewrite common/libsys.c to reflect system calls for that system. This
12 file contains all the really system dependent code that differs between
13 Plan 9 and each Unix. This includes file management, signal
14 handling, process control and error handling.
15 - change the important directory trees in common/mail.c to reflect
16 where you want things like
17 - get the ARGBEGIN/ARGEND/ARGF macros from Plan 9's libc.h
18 - get the include files correct in common/sys.h
19 - rewrite smtp/mxdial to use the conventions of that system
20 - rewrite runq.c to walk queues on that system.