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Traditional Mode |
Traditional (pre-standard) C preprocessing is rather different from
the preprocessing specified by the standard. When GCC is given the
'-traditional-cpp' option, it attempts to emulate a traditional
preprocessor.
GCC versions 3.2 and later only support traditional mode semantics in
the preprocessor, and not in the compiler front ends. This chapter
outlines the traditional preprocessor semantics implemented by GNU.
Note, however, that you cannot use traditional mode preprocessing if
you include header files from the TIGCC Library; this section is
included only for reference, for people who want their programs to
be compilable with traditional compilers.
The implementation does not correspond precisely to the behavior of
earlier versions of GCC, nor to any true traditional preprocessor.
After all, inconsistencies among traditional implementations were a
major motivation for C standardization. However, we intend that it
should be compatible with true traditional preprocessors in all ways
that actually matter.