Bug 5007 - ref string, ref StringBuilder does not work (char**)
Summary: ref string, ref StringBuilder does not work (char**)
Status: RESOLVED FIXED
Alias: None
Product: Runtime
Classification: Mono
Component: Interop ()
Version: unspecified
Hardware: PC Windows
: --- normal
Target Milestone: ---
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2012-05-10 12:07 UTC by Joe
Modified: 2012-05-13 20:44 UTC (History)
3 users (show)

Tags:
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED FIXED

Description Joe 2012-05-10 12:07:54 UTC
The following PInvokes do not work:
        [DllImport("MarshalTest.Unmanaged.dll", CallingConvention = CallingConvention.Cdecl)]
        public static extern void TestString(ref string s);//Does not crash, but the data isn't copied back from unmanaged.

        [DllImport("MarshalTest.Unmanaged.dll", CallingConvention = CallingConvention.Cdecl)]
        public static extern void TestString(ref StringBuilder s);//Crashes with * Assertion at marshal.c:6525, condition `(t->attrs & PARAM_ATTRIBUTE_OUT)' not met

Both work on MS.NET when preallocated.

https://bugzilla.xamarin.com/show_bug.cgi?id=487 may be related.
Comment 1 Zoltan Varga 2012-05-13 10:04:33 UTC
Fixed the first case, and change the second to an exception instead of an assert.
Comment 2 Joe 2012-05-13 10:28:17 UTC
Thanks Zoltan. Is the second case planned to stay as an exception?
Comment 3 Zoltan Varga 2012-05-13 11:01:45 UTC
No.
Comment 4 Zoltan Varga 2012-05-13 20:44:02 UTC
Fixed in master/2.10.