weird __restrict error with g++-2.95.2 + glibc-2.1.93

["Adam J. Richter" <adam at yggdrasil dot com>]

>Submitter-Id:	net
>Originator:	Adam J. Richter
>Organization: Yggdrasil Computing, Inc.

Adam J. Richter     __     ______________   4880 Stevens Creek Blvd, Suite 104
adam@yggdrasil.com     \ /                  San Jose, California 95129-1034
+1 408 261-6630         | g g d r a s i l   United States of America
fax +1 408 261-6631      "Free Software For The Rest Of Us."

>Confidential:	no
>Synopsis:	Possibly bogus g++ complaint about glibc-2.1.93/time/sys/time.h
>Severity:	non-critical
>Priority:	low
>Category:	libc
>Class:		sw-bug
>Release:	libc-2.1.93
>Environment:
	
Host type: i686-pc-linux-gnu
System: Linux baldur 2.4.0-test8 #5 SMP Sat Sep 9 02:52:39 PDT 2000 i686 unknown
Architecture: i686

Addons: linuxthreads

Build CC: gcc
Compiler version: 2.95.2 19991024 (release)
Kernel headers: 2.4.0-test8
Symbol versioning: yes
Build static: yes
Build shared: yes
Build pic-default: no
Build profile: yes
Build omitfp: no
Build bounded: no
Build static-nss: no
Stdio: libio

>Description:

	Sorry if this submission is a duplicate.  I tried to get glibcbug
to also send a copy to gcc-bugs@gcc.gnu.org and to me, and I did not
receive a copy, so I fear that the bug I described yesterday has not
been submitted.  This is my second attempt.

	I know glibc-2.95.2 is not for use in production systems, and I also
realize that this bug is more likely a g++ bug, and may even be
mistakes the developers of all of the effected software.  I am just
submitting this report to the relevant parties in the on the chance
that it is a real bug in g++ or glibc.

	Under glibc-2.1.93, a number of C++ software components,
such as harmony, gmod and a number of others, have been getting the
following g++ error:

/usr/include/sys/time.h:69: two or more data types in declaration of `__tz'

	It turns out that running g++ on a file that contains just the
one line "#include <sys/time.h>" will produce this error.

	/usr/include/sys/time.h is installed from
glibc-2.1.93/time/sys/time.h.  Here is an excerpt of the lines leading up
to line 69 in glibc-2.1.93/time/sys/time.h:

57  #if defined __USE_GNU || defined __USE_BSD
58  typedef struct timezone *__timezone_ptr_t;
59  #else
60  typedef void *__timezone_ptr_t;
61  #endif
62  
63  /* Get the current time of day and timezone information,
64     putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.
65     Returns 0 on success, -1 on errors.
66     NOTE: This form of timezone information is obsolete.
67     Use the functions and variables declared in <time.h> instead.  */
68  extern int gettimeofday (struct timeval *__restrict __tv,
69  			 __timezone_ptr_t __restrict __tz) __THROW;

	Eliminating the __restrict keyword or replacing __timezonee_ptr_t
with either "void*" or "struct timezone*" on line 69 makes the error
go away.

	Bracketting "#include <sys/time.h>" in 'extern "C" {...}' has no
effect.



>How-To-Repeat:

% cat > foo.C << EOF
#include <sys/time.h>
EOF
% g++ -c foo.C
/usr/include/sys/time.h:69: two or more data types in declaration of `__tz'


>Fix:

	Either of the following changes to line 69 of
glibc-2.1.93/time/sys/time.h should be useable workarounds:
		1. delete the "__restrict" keyword, or perhaps just
		   bracket it in "#ifndef __cplusplus"..."#endif"
		2. Even uglier, if "#if defined __USE_GNU || _USE_BSD" to
		   select between the following changes:
			a. replace __timezone_ptr_t with "void*"
			b. replace __timezone_ptr_t with "struct timezone*"

	As for the correct fix, it will probably be apparent to somebody
who is more of a C++ person (I can't really say if the error is in glibc,
g++ or the source code that experiences the error).