no output from -MF

[Harri Porten <harri at trolltech dot com>]

Hi !

I'm have problems with the -M preprocessor options. automake 1.4
produces Makefiles that use the -MD option to produce dependency files.
-MD seems to be obsoleted although still mentioned by the gcc info page.
Will it come back ?

I then found -MF but it doesn't produce any result, i.e. no file is
created:

/* test.c */
#include <string.h>

$ gcc -c -Wp,-M test.c   // works fine

test.o: test.c /usr/include/string.h /usr/include/features.h \
  /usr/include/sys/cdefs.h /usr/include/gnu/stubs.h \
  /usr/local/lib/gcc-lib/i686-pc-linux-gnu/2.97/include/stddef.h

$ gcc -Wp,-MF,test.dep test.c // no output
$ ls test.dep
ls: test.dep: No such file or directory

Using cc1 directly doesn't write to file either.

$ cc1 -MF test.dep test.c
$ ls test.dep
ls: test.dep: No such file or directory

A bug or wrong usage ?

Harri.