Does gcnew throw an exception or set variable to nullptr when it fails to allocate memory?
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I'm trying to create VkImageView which will be binded to index 0.
Here is my VkImageView creation code
void Image::createImageView() {
VkImageViewUsageCreateInfo imageViewUsage;
imageViewUsage.sType=VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO;
imageViewUsage.pNext=nullptr;
imageViewUsage.usage=VK_IMAGE_USAGE_STORAGE_BIT;
VkImageViewCreateInfo viewInfo{};
viewInfo.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO;
viewInfo.pNext=&imageViewUsage;
viewInfo.image = textureImage;
viewInfo.viewType = VK_IMAGE_VIEW_TYPE_2D;
viewInfo.format = VK_FORMAT_R8G8B8A8_UNORM;
viewInfo.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
viewInfo.subresourceRange.baseMipLevel = 0;
viewInfo.subresourceRange.levelCount = 1;
viewInfo.subresourceRange.baseArrayLayer = 0;
viewInfo.subresourceRange.layerCount = 1;
if (vkCreateImageView(device, &viewInfo, nullptr, &textureImageView) != VK_SUCCESS) {
throw std::runtime_error("failed to create texture image view!");
}
}
When I call vkUpdateDescriptorSets I get validation error:
vkCreateImageView: Includes a pNext pointer (pCreateInfo->pNext) to a VkStructureType (VK_STRUCTURE_TYPE_IMAGE_VIEW_USAGE_CREATE_INFO), but its parent extension VK_KHR_maintenance2 has not been enabled. The Vulkan spec states: Each pNext member of any structure (including this one) in the pNext chain must be either NULL or a pointer to a valid instance of VkImageViewASTCDecodeModeEXT, VkImageViewUsageCreateInfo, VkSamplerYcbcrConversionInfo, VkVideoProfileKHR, or VkVideoProfilesKHR
Before this I had set viewInfo.pNext=nullptr; for which I was getting validation error:
Write update to VkDescriptorSet 0xf018750000000004[] allocated with VkDescriptorSetLayout 0x683e70000000002[] binding #0 failed with error message: Attempted write update to image descriptor failed due to: ImageView (VkImageView 0xa3c6870000000008[]) with usage mask 0x6 being used for a descriptor update of type VK_DESCRIPTOR_TYPE_STORAGE_IMAGE does not have VK_IMAGE_USAGE_STORAGE_BIT set
Can someone please help me with some hint how exactly I can solve the error?
The error message tells you exactly what to do. If you use VkImageViewUsageCreateInfo, that means you have to enable maintenance2 extension or in turn Vulkan 1.1 to which it was promoted.
Since you seem surprised by the existence of extensions, it feels likely your use of them is just accidental. You might simply want to stop using the VkImageViewUsageCreateInfo extension struct and always set pNext to NULL.
Can anyone clarify why do I get "Invalid pointer operation" when I attempt to delete TStreamAdapter? Or... how to properly free the memory from TStreamAdapter? It works, if I remove the delete but that causes a memory leak. Even if I use boost::scoped_ptr it also fails with the same error.
Note: I also tried initializing TStreamAdapter with soOwned value, same error.
The code:
HRESULT LoadFromStr(TWebBrowser* WB, const UnicodeString& HTML)
{
if (!WB->Document)
{
WB->Navigate("about:blank");
while (!WB->Document) { Application->ProcessMessages(); }
}
DelphiInterface<IHTMLDocument2> diDoc = WB->Document;
if (diDoc)
{
boost::scoped_ptr<TMemoryStream> ms(new TMemoryStream);
{
boost::scoped_ptr<TStringList> sl(new TStringList);
sl->Text = HTML;
sl->SaveToStream(ms.get(), TEncoding::Unicode);
ms->Position = 0;
}
DelphiInterface<IPersistStreamInit> diPSI;
if (SUCCEEDED(diDoc->QueryInterface(IID_IPersistStreamInit, (void**)&diPSI)) && diPSI)
{
TStreamAdapter* sa = new TStreamAdapter(ms.get(), soReference);
diPSI->Load(*sa);
delete sa; // <-- invalid pointer operation here???
// UPDATED (solution) - instead of the above!!!
// DelphiInterface<IStream> sa(*(new TStreamAdapter(ms.get(), soReference)));
// diPSI->Load(sa);
// DelphiInterface is automatically freed on function end
return S_OK;
}
}
return E_FAIL;
}
Update: I found the solution here - http://www.cyberforum.ru/cpp-builder/thread743255.html
The solution is to use
_di_IStream sa(*(new TStreamAdapter(ms.get(), soReference)));
or...
DelphiInterface<IStream> sa(*(new TStreamAdapter(ms.get(), soReference)));
As it will automatically free the IStream once it is out of scope. At least it should - is there a possible memory leak here? (CodeGuard did not detect any memory leaks).
TStreamAdapter is a TInterfacedObject descendant, which implements reference counting semantics. You are not supposed to delete it at all, you need to let reference counting free the object when it is no longer being referenced by anyone.
Using _di_IStream (which is just an alias for DelphiInterface<IStream>) is the correct way to automate that with a smart pointer. TComInterface<IStream> and CComPtr<IStream> would also work, too.
In hotspot/src/share/vm/utilities/exceptions.hpp, there's some code:
// The THREAD & TRAPS macros facilitate the declaration of functions that throw exceptions.
// Convention: Use the TRAPS macro as the last argument of such a function; e.g.:
//
// int this_function_may_trap(int x, float y, TRAPS)
#define THREAD __the_thread__
#define TRAPS Thread* THREAD
The THREAD macro only use for throw an exception:
// The THROW... macros should be used to throw an exception. They require a THREAD variable to be
// visible within the scope containing the THROW. Usually this is achieved by declaring the function
// with a TRAPS argument.
#define THREAD_AND_LOCATION THREAD, __FILE__, __LINE__
#define THROW_OOP(e) \
{ Exceptions::_throw_oop(THREAD_AND_LOCATION, e); return; }
#define THROW_HANDLE(e) \
{ Exceptions::_throw(THREAD_AND_LOCATION, e); return; }
// the real place to use __the_thread__ macro
void Exceptions::_throw(Thread* thread, const char* file, int line, Handle h_exception, const char* message) {......}
However, I use grep to search all OpenJDK8's code, only to find there's only one place here has this __the_thread__ macro.
Can someone tell me what does the real macro define?
__the_thread__ here is the name of a variable or rather an argument to VM functions that may throw an exception. It is always accessed through a THREAD or TRAPS macro, that's why there are no other references, and the real name of the variable does not matter.
For example, the definition
jint find_field_offset(jobject field, int must_be_static, TRAPS)
is expanded by preprocessor to
jint find_field_offset(jobject field, int must_be_static, Thread* __the_thread__)
I've run into this problem before, but never in a situation like this. I'm completely confused. As the question states, I'm getting the runtime error "Object reference not set to an instance of an object." Using the debugger tools, I think I've pinpointed the problem to this line:
dataFileLocation = path;
The entire function is here:
void DATReader::SetPath(String^ path)
{
if(!File::Exists(path))
{
MessageBox::Show( "DATReader (missing dat file: \n"+path+"\n )", "Error", MessageBoxButtons::OK, MessageBoxIcon::Exclamation);
return;
}
dataFileLocation = path;
}
dataFileLocation is declared here, but nothing is assigned to it:
ref class DATReader
{
private:
System::String^ dataFileLocation;
// ...
}
Now I know the reason I'm getting the error is because dataFileLocation is assigned to nothing. But I'm having problems assigning it. When I add = 0; to it, it won't build because its a ref class. When I try to assigned it to = 0; in the constructor, it yells at me for trying to convert it from a System::String^ to an int. If I assign it to a = gcnew String(""); it builds, but throws the same runtime exception.
I don't get it, am I reading the debugger wrong, and this isn't the source of the problem at all? I've just started to use managed code recently, so I'm confused :\
You may want to check and make sure your DATReader object isn't null as well It may be throwing the exception at your DATReader.SetPath() call.
This is a nicety in C# that's missing in C++/CLI. C# generates code that ensures this can never be null. Easily seen in the debugger by setting a breakpoint on the method and inspecting "this". Here's an example program that reproduces the exception:
#include "stdafx.h"
using namespace System;
ref class Example {
String^ dataFileLocation;
public:
void SetPath(String^ path) {
dataFileLocation = path; // Set breakpoint here and inspect "this"
}
};
int main(array<System::String ^> ^args)
{
Example^ obj /* = gcnew Example */;
obj->SetPath("foo");
return 0;
}
Remove the /* */ comments to fix. Fix your code by looking at the call stack to find the method that forgot to instantiate the object.
Managed C++ uses nullptr for null references. So you can check:
if (path == nullptr) { ... }
or use:
if (!String::IsNullOrEmpty(path))
In the code below I would like to replace Windows WinSock error WSAEINTR=10004 with a generic boost system error code, but how do I map the code I found in the debugger, with the generic enums?
timeout_.expires_from_now(posix_time::seconds(15));
timeout_.async_wait( boost::bind(&cancel_socket_fn,this,_1) );
asio::streambuf rd_buf;
unsigned length = read_until( socket_, rd_buf,delimiter_string, error );
timeout_.cancel();
if(error)
{
// how do I make this portable?
if(error.value()==WSAEINTR) throw request_timeout_exception()
else throw my_asio_exception(error,"Unable to read header");
}
...
cancel_socket_fn(system::error_code e) { socket_.cancel(); }
if (error == boost::asio::error::interrupted)...
And I think here is a design error because if this code is called from the thread where io_service::run() (or similar) is called then cancel_socket_fn() will not be called until read_until() finishes. Or if they are in different threads then here are synchronization problems because timer methods are not thread-safe.