On 05/19/15 08:45, John Baldwin wrote:
On Tuesday, May 19, 2015 12:28:05 AM Pedro Giffuni wrote:
Modified: head/sys/ddb/db_break.c
==============================================================================
--- head/sys/ddb/db_break.c Mon May 18 22:14:06 2015 (r283087)
+++ head/sys/ddb/db_break.c Mon May 18 22:27:46 2015 (r283088)
@@ -155,12 +155,12 @@ db_find_breakpoint_here(db_addr_t addr)
return db_find_breakpoint(db_map_addr(addr), addr);
}
-static boolean_t db_breakpoints_inserted = TRUE;
+static boolean_t db_breakpoints_inserted = true;
This code hasn't been churned to use the boolean type. It still uses
boolean_t, which is plain int. TRUE and FALSE go with this type. true
and false go with the boolean type. This probably makes no difference,
because TRUE happens to be implemented with the same value as true and
there are lots of implicit versions between the types.
Yes, I noticed the return types are still ints. It doesn’t look difficult
to convert it to use a real boolean type. In any case, I would prefer to go
forward (using bool) instead of reverting this change.
That wuld be sideways.
I forgot to mention (again) in my previous reply that boolean_t is a mistake
by me. KNF code doesn't even use the ! operator, but uses explicit
comparison with 0. The boolean_t type and TRUE and FALSE are from Mach.
They were used mainly in ddb and vm, and are still almost never used in
kern. I used to like typedefs and a typedef for boolean types, and didn't
know KNF very well, so in 1995 I moved the declaration of boolean_t from
Mach vm code to sys/types.h to try to popularize it. This was a mistake.
Fortunately, it is still rarely used in core kernel code.
The boolean type is also almost never used for syscalls. In POSIX.1-2001,
<stdbool.h> is inherited from C99, but is never used for any other POSIX
API. Using it for syscalls would mainly cause portability problems.
OK, I do understand the kernel wants to keep the C dialect somewhat limited,
and adding stdbool.h doesn’t buy us any type safety here.
I’ll revert the change (prob. tomorrow though).
I will disagree with Bruce a bit and put my vote in for replacing boolean_t
with bool where it is used. I do think that logically (if not strictly) your
commit is a type mismatch as TRUE/FALSE is for boolean_t and true/false are
for bool. I agree with Bruce that we probably don't want to use bool for
system calls. However, I think using bool in the kernel itself is ok and that
we should replace boolean_t with bool.
I guess it boils down to the dilemma between modernity and common
practice.
OK, I know the current change can't stay as-is, and even Bruce admits
that boolean_t is a mistake, so I think I will give the bool a try.
Thanks for the feedback!
Pedro.
_______________________________________________
svn-src-head@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
