[转]GCC dump preprocessor defines

原文：http://stackoverflow.com/questions/2224334/gcc-dump-preprocessor-defines

 

use -E -dM options instead of -c. Example (outputs them to stdout):

 gcc -dM -E -</dev/null

From the gcc manual:

Instead of the normal output, generate a list of `#define' directives for all the macros defined during the execution of the preprocessor, including predefined macros. This gives you a way of finding out what is predefined in your version of the preprocessor. Assuming you have no file foo.h, the command

`touch foo.h; cpp -dM foo.h`

       will show all the predefined macros.

If you use -dM without the -E option, -dM is interpreted as a synonym for -fdump-rtl-mach.