Runs only the C++ preprocessor on the named C++ programs, requesting that the preprocessor generate makefile dependencies and send the result to the standard output (see make(1) for details about make files and dependencies).
For example:
#include <unistd.h> void main(void) {} |
generates this output:
e.o: e.c e.o: /usr/include/unistd.h e.o: /usr/include/sys/types.h e.o: /usr/include/sys/machtypes.h e.o: /usr/include/sys/select.h e.o: /usr/include/sys/time.h e.o: /usr/include/sys/types.h e.o: /usr/include/sys/time.h e.o: /usr/include/sys/unistd.h |
If you specify -xM and -xMF, the compiler writes all makefile dependency information to the file specified with -xMF. This file is overwritten each time the preprocessor writes to it.
make(1S) (for details about makefiles and dependencies)