Re: Minor Bug in Java directors, and a patch

The JNI method ID pointer gets initialized when the
swig_connect_director method gets called. I agree that the warning is
annoying, but it's not a bug (otherwise, a lot of director calls
wouldn't work.)

IIRC, if one doesn't specify an initializer, most compilers simply
initialize the space to zero. I don't recall what the C or C++
standard says on the subject, off the top of my head.


On Tue, 14 Sep 2004 13:40:43 +0800, Russell Keith-Magee
<russell.magee@xxxxxxxxxxxx> wrote:
> 
> Hi all,
> 
> I've been using Directors in a project; I have had no problem with usage,
> but I am getting an annoying warning during compilation. I've found the
> culprit, and I've attached a patch for the problem.
> 
> Here's a test case. Using the following interface definition:
> --- test.i
> %module(directors="1") test
> %{
> %}
> 
> %feature("director") MyClass;
> 
> class MyClass
> {
> public:
>     virtual ~MyClass() {}
>     virtual int method() = 0;
> };
> ---
> Generate the swig bindings with:
> 
> swig -c++ -java -o test_wrap.cpp test.i
> 
> When compiled on a gcc3 compiler with -Wall, generates the warning:
> 
> missing initializer for member
> SwigDirector_MyClass::swig_connect_director(JNIEnv *, _jobject*, _jclass
> *)::<anonymous struct>::base_methid
> 
> The problem is caused by the structure that is defined to store the virtual
> method names, parameter types, and JNI method ID's. The method name and
> parameter types are filled in, but the JNI method ID is left uninitialized.
> 
> This doesn't generate a warning under gcc2.96, or under Visual Studio 6.
> 
> The following patch fixes the problem. All it does is specify an
> initialization value of NULL for the JNI method ID. The fix is on line 3506
> of Modules/java.cxx.
> 
> *** java.cxx.fix        Tue Sep 14 13:00:06 2004
> --- java.cxx.old        Tue Sep 14 12:58:28 2004
> ***************
> *** 3503,3509 ****
>         for (int i = first_class_dmethod; i < curr_class_dmethod; ++i) {
>           UpcallData       *udata = Getitem(dmethods_seq, i);
> 
> !         Printf(w->def, "{ \"%s\", \"%s\", NULL }", Getattr(udata,
> "method"), Geta
> ttr(udata, "fdesc"));
>           if (i != curr_class_dmethod - 1)
>             Putc(',', w->def);
>           Putc('\n', w->def);
> --- 3503,3509 ----
>         for (int i = first_class_dmethod; i < curr_class_dmethod; ++i) {
>           UpcallData       *udata = Getitem(dmethods_seq, i);
> 
> !         Printf(w->def, "{ \"%s\", \"%s\" }", Getattr(udata, "method"),
> Getattr
> (udata, "fdesc"));
>           if (i != curr_class_dmethod - 1)
>             Putc(',', w->def);
>           Putc('\n', w->def);
> 
> Yours,
> Russ Magee
> 
> --
> Dr Russell Keith-Magee <russell.magee@xxxxxxxxxxxx>
> Software Engineer
> Calytrix Technologies
> Ph:  +61 8 9325 5600
> Fax: +61 8 9325 5400

Dr. Scott Michel <scottm@xxxxxxxx>
Senior Member, Technical Staff
The Aerospace Corporation
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