http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39080
Shakthi Kannan <skannan at redhat dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |skannan at redhat dot com --- Comment #2 from Shakthi Kannan <skannan at redhat dot com> --- The preprocessor documentation page mentions that the options need to be run on each C source file: "3.11 Options Controlling the Preprocessor These options control the C preprocessor, which is run on each C source file before actual compilation." Source: http://gcc.gnu.org/onlinedocs/gcc-4.8.0/gcc/Preprocessor-Options.html#Preprocessor-Options