Is there a way to include a header in each compilation unit without changing each source file?

Question

Given the following:

• large project with thousands of C ++ source files
• no common header file (not a single header that is included in each source file)
• the specified project is compiled with g ++ and managed by make

Is it possible to include a definition (for example, a macro) in each compilation unit without changing each source file to include a new header file?

Answer 1

From the gcc man:

-include file

, #include "    .    -    . ,    " #include "..."    .    include,   , .

Answer 2

"-D" gcc.

: gcc -ansi -Wall -Dblah='mymacrohere()' blah.cpp

: GCC, ,