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[Bug c++/34772] self-initialisation does not silence uninitialised warnings (-Winit-self ignored)
- From: "manu at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 14 Jan 2008 01:27:42 -0000
- Subject: [Bug c++/34772] self-initialisation does not silence uninitialised warnings (-Winit-self ignored)
- References: <bug-34772-2228@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #4 from manu at gcc dot gnu dot org 2008-01-14 01:27 -------
(In reply to comment #3)
> I think it would be better to fix the documentation to reflect the current
> behaviour for C++/ObjC++, and mark this bug as an enhancement request.
It is a bit misleading providing -Winit-self when it has no effect and when it
cannot be disabled. But your argument about breaking existing code is solid.
So, of course, I will only update the documentation:
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi (revision 130605)
+++ gcc/doc/invoke.texi (working copy)
@@ -2827,14 +2827,15 @@
@option{-Wnonnull} is included in @option{-Wall} and @option{-Wformat}. It
can be disabled with the @option{-Wno-nonnull} option.
-@item -Winit-self @r{(C, C++, Objective-C and Objective-C++ only)}
+@item -Winit-self @r{(C and Objective-C only)}
@opindex Winit-self
Warn about uninitialized variables which are initialized with themselves.
Note this option can only be used with the @option{-Wuninitialized} option,
which in turn only works with @option{-O1} and above.
-For example, GCC will warn about @code{i} being uninitialized in the
-following snippet only when @option{-Winit-self} has been specified:
+For C and Objective-C, GCC will silence the warning about @code{i}
+being uninitialized in the following snippet unless
+@option{-Winit-self} has been specified:
@smallexample
@group
int f()
@@ -3094,11 +3095,12 @@
These warnings are possible only in optimizing compilation,
because they require data flow information that is computed only
when optimizing. If you do not specify @option{-O}, you will not get
-these warnings. Instead, GCC will issue a warning about
@option{-Wuninitialized}
-requiring @option{-O}.
+these warnings. Instead, GCC will issue a warning about
+@option{-Wuninitialized} requiring @option{-O}.
-If you want to warn about code which uses the uninitialized value of the
-variable in its own initializer, use the @option{-Winit-self} option.
+For C and Objective-C, using the uninitialized value of the variable in its
+own initializer (e.g. @samp{int i = i;}) silences the warning. If you
+want to warn about such code use the @option{-Winit-self} option.
These warnings occur for individual uninitialized or clobbered
elements of structure, union or array variables as well as for
--
manu at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
Summary|-Winit-self ignored when |self-initialisation does not
|compiling C++ (and ObjC++) |silence uninitialised
| |warnings (-Winit-self
| |ignored)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34772