[Bug preprocessor/25717] [3.4/4.0/4.1/4.2 Regression] -dM does not list all defined macros (in particular, __STDC__)

[steven at gcc dot gnu dot org]

------- Comment #4 from steven at gcc dot gnu dot org  2006-01-09 21:57 -------
Your command line:

   touch test.h; gcc -dM test.h

creates a precompiled header.

Also, my documentation for -dM says:

@item -dM
@itemx -fdump-rtl-mach
@opindex dM
@opindex fdump-rtl-mach
Dump after performing the machine dependent reorganization pass, to
@file{@var{file}.35.mach}.


What you want is -dD.  But I'm not sure what that is supposed to write out. 
GCC 3.3, 4.0, and 4.1 all give no output at all for an empty file, or a file
with a single #define.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25717