Re: preprocessor/5899: -M disables -dM

[Andreas Schwab <schwab@suse.de>]

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The following reply was made to PR preprocessor/5899; it has been noted by GNATS.

From: Andreas Schwab <schwab@suse.de>
To: Neil Booth <neil@daikokuya.demon.co.uk>
Cc: neil@gcc.gnu.org, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org,
	gcc-gnats@gcc.gnu.org
Subject: Re: preprocessor/5899: -M disables -dM
Date: Sat, 09 Mar 2002 21:50:56 +0100

 Neil Booth <neil@daikokuya.demon.co.uk> writes:
 
 |> Andreas Schwab wrote:-
 |> 
 |> > IMHO neither -dM nor -M produce "normal output", so it would not
 |> > contradict the docs to output both.
 |> 
 |> Sure, but it wasn't mentioned that it outputs to two streams
 |> simultaneously.  2.95 didn't.
 |> 
 |> > Both 2.95 and 3.0.4 behave as expected by glibc.
 |> 
 |> What is "expected by glibc"?  It's not what you posted, since 2.95.4
 |> didn't support -MF.
 
 glibc uses the equivalent functionality provided by SUNPRO_DEPENDENCIES:
 
 # Generate the list of SYS_* macros for the system calls (__NR_* macros).
 $(objpfx)syscall-%.h $(objpfx)syscall-%.d: ../sysdeps/unix/sysv/linux/sys/syscall.h
 	rm -f $(@:.h=.d)-t
 	{ \
 	 echo '/* Generated at libc build time from kernel syscall list.  */';\
 	 echo ''; \
 	 echo '#ifndef _SYSCALL_H'; \
 	 echo '# error "Never use <bits/syscall.h> directly; include <sys/syscall.h> instead."'; \
 	 echo '#endif'; \
 	 echo ''; \
 	 SUNPRO_DEPENDENCIES='$(@:.h=.d)-t $@' \
 	 $(CC) -E -x c $(sysincludes) $< -D_LIBC -dM | \
 	 sed -n 's@^#define __NR_\([^ ]*\) .*$$@#define SYS_\1 __NR_\1@p'; \
 	} > $(@:.d=.h).new
 	mv -f $(@:.d=.h).new $(@:.d=.h)
 	sed < $(@:.h=.d)-t > $(@:.h=.d)-t2 \
 	    -e 's,$(subst .,\.,$@),$(patsubst $(objpfx)%,$$(objpfx)%,\
 					      $(@:.d=.h) $(@:.h=.d)),'
 	rm -f $(@:.h=.d)-t
 	mv -f $(@:.h=.d)-t2 $(@:.h=.d)
 
 Andreas.
 
 -- 
 Andreas Schwab, SuSE Labs, schwab@suse.de
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