[Kde-bindings] playground/bindings/kimono

[Richard Dale]

On Thursday 19 October 2006 18:15, Arno Rehn wrote:
> SVN commit 597228 by arnorehn:
>
> * Added support for marshalling C++-QStringLists to C#-ArrayLists
>   (not tested yet)
>
> CCMAIL: kde-bindings at kde.org
>
>
>
>  M  +5 -0      ChangeLog  
>  M  +31 -1     SmokeInvocation.cs  
>  M  +53 -14    handlers.cpp  
I tried a test with this code:

ArrayList test = QColor.ColorNames();

foreach (string str in test) {
    Console.WriteLine("color: {0}", str);
}

The QStringList was being passed correctly to the marshaller. Then I added 
some printfs:

char **
QStringListToStringArray(void* ptr)
{
printf("QStringListToStringArray: ptr: %p\n", ptr);
	QStringList * s = (QStringList*) ptr;
	char ** result = (char **) calloc(s->count(), sizeof(char *));
	
	for (int i = 0; i < s->count(); i++) {
		result[i] = strdup((*s)[i].toLatin1().constData());
 printf("QStringListToStringArray: s: %s\n", (*s)[i].toLatin1().constData());
	}
	return result;
}

and the array was still there ok. However when it returned in 
SmokeInvocation.cs, there was a null reference in 'string[] s' and it failed:

		static IntPtr QStringListToArrayList(IntPtr ptr) {
Console.WriteLine("ENTER QStringListToArrayList ptr: {0}", ptr);

			string[] s = QStringListToStringArray(ptr);
Console.WriteLine("QStringListToArrayList s: {0}", s);
Console.WriteLine("QStringListToArrayList s[0]: {0}", s[0]);
			ArrayList al = new ArrayList(s);
			return (IntPtr) GCHandle.Alloc(al);
		}

Unhandled Exception: System.NullReferenceException: Object reference not set 
to an instance of an object
in <0x0023a> System.String:FormatHelper (System.Text.StringBuilder result, 
IFormatProvider provider, System.String format, System.Object[] args)
in <0x0002b> System.String:Format (IFormatProvider provider, System.String 
format, System.Object[] args)
in <0x0000f> System.String:Format (System.String format, System.Object[] args)
in <0x00012> System.IO.TextWriter:Write (System.String format, System.Object[] 
arg)
in <0x00014> System.IO.TextWriter:WriteLine (System.String format, 
System.Object[] arg)
in <0x0002e> System.IO.SynchronizedWriter:WriteLine (System.String format, 
System.Object[] value)
in <0x00018> System.Console:WriteLine (System.String format, System.Object[] 
arg)
in <0x00044> Qyoto.SmokeInvocation:QStringListToArrayList (IntPtr ptr)

How is the 'char **' array terminated - does it expect a null entry at the 
end?

I was going to add entries to the array one by one while iterating through the 
QStringList and calling a method on C# side for each one, rather than do them 
all at once. 

-- Richard