gibbed/SteamAchievementManager · error · ArgumentNullException

data

Error message

data

What it means

Wrappers.SteamUtils005.GetImageRGBA throws ArgumentNullException (message "data") when the caller passes a null byte[] buffer. The method needs a pre-allocated buffer of the image's size to fill via the native GetImageRGBA call; null means no destination was provided.

Solutions

1. Query the image dimensions and allocate a byte[w*h*4] buffer before calling GetImageRGBA
2. Guard against null before calling, or ensure the buffer field is initialized
3. Reuse a cached correctly-sized buffer per image index

Example fix

// before
utils.GetImageRGBA(index, null);
// after
utils.GetImageSize(index, out var w, out var h);
var data = new byte[w * h * 4];
utils.GetImageRGBA(index, data);

if (data == null) { utils.GetImageSize(index, out var w, out var h); data = new byte[w * h * 4]; }

static bool IsValidImageBuffer(byte[] data) => data is { Length: > 0 };

try { utils.GetImageRGBA(index, data); }
catch (ArgumentNullException)
{
    // allocate correctly-sized buffer and retry
}

When it happens

Trigger: Calling GetImageRGBA(index, data) with data == null, typically because the caller skipped querying the image size (GetImageSize) and allocating the array.

Common situations: Copying sample code without the size-query step; passing an uninitialized field; caching the buffer lazily and forgetting the first allocation.

Related errors

• failed to get Steam install path
• failed to load SteamClient
• failed to create ISteamClient018
• failed to create pipe
• failed to connect to global user

AI-assisted analysis of gibbed/SteamAchievementManager@de8b71048a (2026-09-12). Data as JSON: /api/errors/bb2ede7982b0d5e0. Report an issue: GitHub.

Appendix: source

Thrown at SAM.API/Wrappers/SteamUtils005.cs:73

        private delegate bool NativeGetImageSize(IntPtr self, int index, out int width, out int height);

        public bool GetImageSize(int index, out int width, out int height)
        {
            var call = this.GetFunction<NativeGetImageSize>(this.Functions.GetImageSize);
            return call(this.ObjectAddress, index, out width, out height);
        }
        #endregion

        #region GetImageRGBA
        [UnmanagedFunctionPointer(CallingConvention.ThisCall)]
        [return: MarshalAs(UnmanagedType.I1)]
        private delegate bool NativeGetImageRGBA(IntPtr self, int index, byte[] buffer, int length);

        public bool GetImageRGBA(int index, byte[] data)
        {
            if (data == null)
            {
                throw new ArgumentNullException("data");
            }
            var call = this.GetFunction<NativeGetImageRGBA>(this.Functions.GetImageRGBA);
            return call(this.ObjectAddress, index, data, data.Length);
        }
        #endregion

        #region GetAppID
        [UnmanagedFunctionPointer(CallingConvention.ThisCall)]
        private delegate uint NativeGetAppId(IntPtr self);

        public uint GetAppId()
        {
            return this.Call<uint, NativeGetAppId>(this.Functions.GetAppID, this.ObjectAddress);
        }
        #endregion
    }
}

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