gcc/doc/cpp/traditional-mode.rst

   1 ..
   2   Copyright 1988-2022 Free Software Foundation, Inc.
   3   This is part of the GCC manual.
   4   For copying conditions, see the copyright.rst file.
   5
   6 .. _traditional-mode:
   7
   8 Traditional Mode
   9 ----------------
  10
  11 Traditional (pre-standard) C preprocessing is rather different from
  12 the preprocessing specified by the standard.  When the preprocessor
  13 is invoked with the
  14 :option:`-traditional-cpp` option, it attempts to emulate a traditional
  15 preprocessor.
  16
  17 This mode is not useful for compiling C code with GCC,
  18 but is intended for use with non-C preprocessing applications.  Thus
  19 traditional mode semantics are supported only when invoking
  20 the preprocessor explicitly, and not in the compiler front ends.
  21
  22 The implementation does not correspond precisely to the behavior of
  23 early pre-standard versions of GCC, nor to any true traditional preprocessor.
  24 After all, inconsistencies among traditional implementations were a
  25 major motivation for C standardization.  However, we intend that it
  26 should be compatible with true traditional preprocessors in all ways
  27 that actually matter.
  28
  29 .. toctree::
  30   :maxdepth: 2
  31
  32   traditional-lexical-analysis
  33   traditional-macros
  34   traditional-miscellany
  35   traditional-warnings