.. -*- coding: utf-8; -*-

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 cpp (C preprocessor).

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.. contents::

   :local:

How to see macros expansion?

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GCC::

  $ cpp <file>.c

MSVC::

  $ cl /E <file>.c

Under Emacs select region and type ``C-c C-e``.

How to see predefined macros?

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See:

http://predef.sourceforge.net/

  ``predef`` project on Sourceforge

http://en.wikipedia.org/wiki/C_preprocessor#Compiler-specific_predefined_macros

  Compiler specific predefined macros

http://msdn.microsoft.com/en-us/library/b0084kay.aspx

  Predefined Macros

GNU C Compiler::

  $ gcc -dM -E - < /dev/null

HP-UX ansi C compiler::

  $ cc -v EMPTY.c

SCO OpenServer C compiler::

  $ cc -## EMPTY.c

Sun Studio C/C++ compiler::

  $ cc -## EMPTY.c

IBM AIX XL C/C++ compiler::

  $ cc -qshowmacros -E EMPTY.c

For Visual Studio compiler there no any possibility get predefined macros from

command line... But some macros documented:

``_MSC_VER``

  Defines the compiler version. Always defined.

``_WIN32``

  Defined for applications for Win32. Always defined.