A user that uses "info gcc" to look for details about the preprocessor
doesn't find them. Example: [Bug c/29994]. The user did "info gcc",
was looking for a section that explains all the predefined preprocessor
macros, but didn't find it. The reason was that they are in a separate
Nowadays the preprocessor is rarely used on its own. To the user, it
appears as part of the compiler.
Suggestion: Integrate the parts of cpp.info that don't apply to other
C/C++ implementations (such as "Predefined Macros" and "Invocation", and
possibly others) into the gcc.info manual.
I don't see why it has to be part of the GCC manual. This is like saying users think as and ld are part of the compiler and really should also be included in the manual.