pdp11-cpp

The C preprocessor — the pristine 2.9BSD cpp (Reiser lineage), built with FLEXNAMES so macro names go to 128 characters like the native 2.9 binary.

pdp11-cpp [-P] [-E] [-R] [-Dname[=val]] [-Uname] [-Idir] [-C] [in [out]]

• Two fixes the 2.8 revision lacks: the defined(NAME) / flslvl state leak is gone (the 2.8 behaviour is preserved as a golden record in tests/cpp-bsd28/), and #include <...> is scanned with macro expansion off.
• Era headers without flags. The default system include directory is ../include/<universe>/ resolved relative to the binary ($PDP11_UNIVERSE, default bsd29), with a flat ../include/ as fallback — the same relocatable scheme cc and ld use.
• Faithful output. FLEXNAMES only widens cpp's internal name table; the emitted text is unchanged, which is what lets downstream byte-match oracles work.

Documentation

• Design — the macro and table model, FLEXNAMES, and the include machinery.
• User guide — the options and preprocessing examples.
• docs/porting.md — the LP64 porting guide (K&R varargs, the yacc'd #if grammar, table sizes).

Build and test

make          # builds ../../bin/pdp11-cpp (yacc generates cpy.c)
make check    # covered by the cpp golden tests in tests/cpp/ at the
              # repo root (run.sh -u regenerates the .expected files)