Burst don't allow me to create a NativeArray

The documentations says:

1) Burst supports the following primitive types:

• bool
• char
• sbyte/byte
• short/ushort
• int/uint
• long/ulong
• float
• double

2) Burst supports regular structs with any field with supported types.

3) Managed arrays are not supported by burst. You should use instead a native container, NativeArray<T> for instance.

Based on that I'm trying to create a native array like this:

Code (CSharp):

1.  
2.  [BurstCompile]
3.       struct MainJob : IJobParallelFor {
4.  
5.          struct Obstacle{
6.             public int   Distance;
7.             public float X1;
8.             public float X2;
9.             public float Speed;
10.          }
11.  
12.          public int length;
13.  
14.          public void Execute(int index) {
15.  
16.                NativeArray<Obstacle> LeftObst = new NativeArray<Obstacle>(length,Allocator.TempJob);
17.  
18.                LeftObst.Dispose();
19.          }
20.    }
21.  

but I'm getting this error:

C:\buildslave\unity\build\Runtime\Export\NativeArray\DisposeSentinel.cs(49,9): error: Using managed `null` is not supported by burst

While processing function `System.Void Unity.Collections.LowLevel.Unsafe.DisposeSentinel::Create(Unity.Collections.LowLevel.Unsafe.AtomicSafetyHandle&,Unity.Collections.LowLevel.Unsafe.DisposeSentinel&,System.Int32,Unity.Collections.Allocator)`

While compiling job: System.Void Unity.Jobs.IJobParallelForExtensions/ParallelForJobStruct`1<Casablanca.ECS.SysAvoidCollision/MainJob>::Execute(T&,System.IntPtr,System.IntPtr,Unity.Jobs.LowLevel.Unsafe.JobRanges&,System.Int32)

Compiler exception: System.NotSupportedException: Using managed `null` is not supported by burst
at Burst.Compiler.IL.ILVisitor.NotSupported (Burst.Compiler.IL.Syntax.ILInstruction inst) [0x0016b] in <1ba7ce5f379b46f08028b383607c2c83>:0
at Burst.Compiler.IL.ILVisitor.CompileInternal (Burst.Compiler.IL.Syntax.ILInstruction inst) [0x00523] in <1ba7ce5f379b46f08028b383607c2c83>:0
at Burst.Compiler.IL.ILVerifier.CompileInternal (Burst.Compiler.IL.Syntax.ILInstruction inst) [0x00000] in <1ba7ce5f379b46f08028b383607c2c83>:0

 

Like Joachim says - is not supported yet, and documentation says about public fields for pushing data outside job in to him, not about allocation inside job.

 

Obviously what you say is true, however I read again the documentation and I didn't find any reference about such limitation.

 

Not sure if this has been fixed yet for the latest preview, otherwise there is an unsafe workaround if you want to use it for short arrays or slices:

Code (CSharp):

1.  
2. const int maxPolyCount = 32;
3. var polyPtr = stackalloc PolygonId[maxPolyCount];
4. var polyPath = NativeSliceUnsafeUtility.ConvertExistingDataToNativeSlice<PolygonId>(polyPtr, sizeof(PolygonId), maxPolyCount);
5. NativeSliceUnsafeUtility.SetAtomicSafetyHandle(ref polyPath, AtomicSafetyHandle.GetTempUnsafePtrSliceHandle());
6.  

/Jannek

 

Hi, sorry for poking an old thread

was there any updated to this?

is it supported in a newer burst version?

or what is the correct way to use temp NativeArrays inside a job?

getting

Code (CSharp):

1. C:\buildslave\unity\build\Runtime\Export\NativeArray\DisposeSentinel.cs(54,28): error: Creating a managed object `Unity.Collections.LowLevel.Unsafe.DisposeSentinel..ctor(...)` is not supported by burst
2. at Unity.Collections.LowLevel.Unsafe.DisposeSentinel.Create(ref Unity.Collections.LowLevel.Unsafe.AtomicSafetyHandle safety, ref Unity.Collections.LowLevel.Unsafe.DisposeSentinel sentinel, int callSiteStackDepth, Unity.Collections.Allocator allocator) (at C:\buildslave\unity\build\Runtime\Export\NativeArray\DisposeSentinel.cs:54)
3. at Unity.Collections.NativeList`1<Passenger_Manager_Jobs.class_origin_planet_picklist>..ctor(Unity.Collections.NativeList`1<Passenger_Manager_Jobs.class_origin_planet_picklist>* this, int capacity, Unity.Collections.Allocator i_label, int stackDepth) (at C:\Users\chris\Documents\InterstellarTransportCompany\Library\PackageCache\com.unity.collections@0.0.9-preview.12\Unity.Collections\NativeList.cs:71)
4. at Unity.Collections.NativeList`1<Passenger_Manager_Jobs.class_origin_planet_picklist>..ctor(Unity.Collections.NativeList`1<Passenger_Manager_Jobs.class_origin_planet_picklist>* this, Unity.Collections.Allocator i_label) (at C:\Users\chris\Documents\InterstellarTransportCompany\Library\PackageCache\com.unity.collections@0.0.9-preview.12\Unity.Collections\NativeList.cs:38)
5. at Passenger_Manager_Jobs.SpawnWeeklyPassengersForPlanetoidJob.Execute(Passenger_Manager_Jobs.SpawnWeeklyPassengersForPlanetoidJob* this, int index) (at C:\Users\chris\Documents\InterstellarTransportCompany\Assets\Scripts\Passenger_Manager_Jobs.cs:179)
6. at Unity.Jobs.IJobParallelForExtensions.ParallelForJobStruct`1<Passenger_Manager_Jobs.SpawnWeeklyPassengersForPlanetoidJob>.Execute(ref Passenger_Manager_Jobs.SpawnWeeklyPassengersForPlanetoidJob jobData, System.IntPtr additionalPtr, System.IntPtr bufferRangePatchData, ref Unity.Jobs.LowLevel.Unsafe.JobRanges ranges, int jobIndex) (at C:\buildslave\unity\build\Runtime\Jobs\Managed\IJobParallelFor.cs:43)
7.  
8.  
9. While compiling job: System.Void Unity.Jobs.IJobParallelForExtensions/ParallelForJobStruct`1<Passenger_Manager_Jobs/SpawnWeeklyPassengersForPlanetoidJob>::Execute(T&,System.IntPtr,System.IntPtr,Unity.Jobs.LowLevel.Unsafe.JobRanges&,System.Int32)
10.  

 

Show code. NativeArrays allocated with temp allocator inside job works fine in bursted job. And on which unity and dots packages versions you are?

 

unity 2018.4.14 LTS
burst 1.2.0-preview.11

sample job code, works without temp_array but adding any temp array gives burst compile error

Code (CSharp):

1. [BurstCompile]
2.     struct SampleParallelJob : IJobParallelFor
3.     {
4.         [ReadOnly]
5.         public NativeArray<JobValues> job_values;
6.  
7.         [ReadOnly]
8.         public NativeList<MoreValues> more_values;
9.  
10.         [WriteOnly]
11.         public NativeMultiHashMap<int, JobResult>.Concurrent job_results;
12.  
13.         public void Execute(int index)
14.         {
15.             var temp_array = new NativeList<MoreValues>(Allocator.Temp);
16.  
17.             var job_value = job_values[index];
18.  
19.             for (int i = job_value.more_values_array_start_index; i < job_value.more_values_array_start_index + job_value.more_values_array_length; i++)
20.             {
21.                 var result = more_values[i].other_value;
22.                 var other_result = more_values[i].value;
23.                 job_results.Add(index, new JobResult(result, other_result));
24.             }
25.  
26.             temp_array.Dispose();
27.         }
28.     }

 

I believe NativeList is one native container type which still has this restriction. Using a NativeArray should work, though.

 

You on old version of unity and packages. It’s not supported, use 2019.2 and above, better is 2019.3 and latest DOTS packages.

 

NativeList works fine, NativeQueue allocation inside job not supported.

 

will wait out the 2019 LTS version