Am I creating a PtrArray the right way?

[alansartorio]

I'm using this binding generator to create a binding for libfprint and I found that PtrArray isn't always supported by the source generator, so I wanted to write the function binding manually.
I need to pass a PtrArray to this function, so I found that I can create a PtrArray instance by using new GLib.PtrArray(), but I noticed that sometimes it causes this critical log to be printed:

(process:1): GLib-CRITICAL **: 05:07:59.274: g_atomic_ref_count_dec: assertion 'old_value > 0' failed

Am I doing anything wrong?

In case it's helpful, I found I can replicate the issue by following these steps:

1. dotnet new console -n PtrArrayTest
2. cd PtrArrayTest
3. dotnet add package GirCore.GLib-2.0 --version 0.7.0-preview.3
4. Write Program.cs:

GLib.Module.Initialize();

while (true) {
    using var arr = new GLib.PtrArray();

    Thread.Sleep(100);
}

6. dotnet run

It prints repeatedly:

(process:736168): GLib-CRITICAL **: 02:28:09.968: g_atomic_ref_count_dec: assertion 'old_value > 0' failed

[badcel]

I will check in the coming days. Thanks for the detailed report.

[badcel]

This is actually some kind of bug in GirCore. PtrArray is a record from GObject perspective. I assumed that records can just be created manually in memory. Which is at least not true for PtrArray as it requires some specific initialization.

Unfortunately there is not even the New function be generated which would do this for you.

A workaround for now is to call the new method manually:

using System.Runtime.InteropServices;

Console.WriteLine("Hello, World!");

GLib.Module.Initialize();

while (true)
{
    var handle = new GLib.Internal.PtrArrayOwnedHandle(New());
    using var arr = new GLib.PtrArray(handle);
    Thread.Sleep(100);
}

[DllImport("libgobject-2.0.so.0", EntryPoint = "g_ptr_array_new")]
static extern nint New();

You need to update your dllimport to the one matching your system. It probably is:

• Windows: "libgobject-2.0-0.dll"
• Linux: "libgobject-2.0.so.0"
• Mac: "libgobject-2.0.0.dylib"

Edit: The api in general is not very usable in the moment. You would need to workaround the missing stuff yourself. There is #748 to improve the situation. I created #1349 as a first step. But more work is needed. Feel free to contribute.

[alansartorio]

Thank you for looking into this and helping out.
I opened #1351 to add the public bindings for some PtrArray methods.