Access Violation Exception EnterCriticalSection WinAPI C#

huangapple
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英文:

Access Violation Exception EnterCriticalSection WinAPI C#

问题

我不明白是什么导致了这个错误。

  1. [DllImport("kernel32.dll")]
  2. static extern void EnterCriticalSection(ref IntPtr lpCriticalSection);
  4. [DllImport("kernel32.dll")]
  5. static extern void LeaveCriticalSection(ref IntPtr lpCriticalSection);
  7. public Form1()
  8. {
  9.    InitializeComponent();
  10. }
  12. private void button1_Click(object sender, EventArgs e)
  13. {
  14.     unsafe
  15.     {
  16.         try
  17.         {
  18.             IntPtr criticalSection = new IntPtr();
  19.             EnterCriticalSection(ref criticalSection);
  20.             LeaveCriticalSection(ref criticalSection);
  21.         }
  22.         catch (AccessViolationException exception)
  23.         {
  24.             Console.WriteLine(exception.Message);
  25.         }
  26.     }
  27. }

我尝试在Visual Studio中将生成类型从Any CPU更改为x86，但没有产生结果。

英文:

I don't understand what is causing this error

  1. [DllImport("kernel32.dll")]
  2. static extern void EnterCriticalSection(ref IntPtr lpCriticalSection);
  4. [DllImport("kernel32.dll")]
  5. static extern void LeaveCriticalSection(ref IntPtr lpCriticalSection);
  7. public Form1()
  8. {
  9.    InitializeComponent();
  10. }
  12. private void button1_Click(object sender, EventArgs e)
  13. {
  14.     unsafe
  15.     {
  16.         try
  17.         {
  18.             IntPtr criticalSection = new IntPtr();
  19.             EnterCriticalSection(ref criticalSection);
  20.             LeaveCriticalSection(ref criticalSection);
  21.         }
  22.         catch (AccessViolationException exception)
  23.         {
  24.             Console.WriteLine(exception.Message);
  25.         }
  26.     }
  27. }

I tried in Visual Studio to change the build type from Any CPU to x86, but it didn't bring results.

答案1

得分: 0

EnterCriticalSection() 需要接收一个已经使用 InitializeCriticalSection() 或 InitializeCriticalSectionAndSpinCount() 初始化过的 CRITICAL_SECTION 结构体的指针作为参数。

但是，您却传递了一个未初始化的 IntPtr 的引用，它并没有指向有意义的位置。因此，当 EnterCriticalSection() 尝试访问一个不存在的结构体时，程序会崩溃。

正确的代码应该类似于以下内容：

  1. [StructLayout(LayoutKind.Sequential)]
  2. public struct CRITICAL_SECTION
  3. {
  4.     public IntPtr DebugInfo;
  5.     public int LockCount;
  6.     public int RecursionCount;
  7.     public IntPtr OwningThread;
  8.     public IntPtr LockSemaphore;
  9.     public UIntPtr SpinCount;
  10. }
  12. [DllImport("kernel32.dll")]
  13. static extern void InitializeCriticalSection(ref CRITICAL_SECTION lpCriticalSection);
  15. [DllImport("kernel32.dll")]
  16. static extern void DeleteCriticalSection(ref CRITICAL_SECTION lpCriticalSection);
  18. [DllImport("kernel32.dll")]
  19. static extern void EnterCriticalSection(ref CRITICAL_SECTION lpCriticalSection);
  21. [DllImport("kernel32.dll")]
  22. static extern void LeaveCriticalSection(ref CRITICAL_SECTION lpCriticalSection);
  24. public Form1()
  25. {
  26.    InitializeComponent();
  27. }
  29. private void button1_Click(object sender, EventArgs e)
  30. {
  31.     unsafe
  32.     {
  33.         try
  34.         {
  35.             CRITICAL_SECTION criticalSection = new CRITICAL_SECTION();
  36.             InitializeCriticalSection(ref criticalSection);
  37.             EnterCriticalSection(ref criticalSection);
  38.             LeaveCriticalSection(ref criticalSection);
  39.             DeleteCriticalSection(ref criticalSection);
  40.         }
  41.         catch (AccessViolationException exception)
  42.         {
  43.             Console.WriteLine(exception.Message);
  44.         }
  45.     }
  46. }

然而，在C#中，您实际上不需要使用 CRITICAL_SECTION，可以使用 lock 语句 或者类似 System.Threading.Monitor 的同步原语。

英文:

EnterCriticalSection() expects to be given a pointer to a CRITICAL_SECTION struct that has been initialized with either InitializeCriticalSection() or InitializeCriticalSectionAndSpinCount().

But instead, you are giving it a reference to an uninitialized IntPtr that doesn't point anywhere meaningful. Hence the crash when EnterCriticalSection() tries to access a struct that doesn't exist.

The correct code should look more like this:

  1. [StructLayout(LayoutKind.Sequential)]
  2. public struct CRITICAL_SECTION
  3. {
  4.     public IntPtr DebugInfo;
  5.     public int LockCount;
  6.     public int RecursionCount;
  7.     public IntPtr OwningThread;
  8.     public IntPtr LockSemaphore;
  9.     public UIntPtr SpinCount;
  10. }
  12. [DllImport("kernel32.dll")]
  13. static extern void InitializeCriticalSection(ref CRITICAL_SECTION lpCriticalSection);
  15. [DllImport("kernel32.dll")]
  16. static extern void DeleteCriticalSection(ref CRITICAL_SECTION lpCriticalSection);
  18. [DllImport("kernel32.dll")]
  19. static extern void EnterCriticalSection(ref CRITICAL_SECTION lpCriticalSection);
  21. [DllImport("kernel32.dll")]
  22. static extern void LeaveCriticalSection(ref CRITICAL_SECTION lpCriticalSection);
  24. public Form1()
  25. {
  26.    InitializeComponent();
  27. }
  29. private void button1_Click(object sender, EventArgs e)
  30. {
  31.     unsafe
  32.     {
  33.         try
  34.         {
  35.             CRITICAL_SECTION criticalSection = new CRITICAL_SECTION();
  36.             InitializeCriticalSection(ref criticalSection);
  37.             EnterCriticalSection(ref criticalSection);
  38.             LeaveCriticalSection(ref criticalSection);
  39.             DeleteCriticalSection(ref criticalSection);
  40.         }
  41.         catch (AccessViolationException exception)
  42.         {
  43.             Console.WriteLine(exception.Message);
  44.         }
  45.     }
  46. }

However, you really don't need to use CRITICAL_SECTION in C#, use the lock statement instead, or a synchronization primitive like System.Threading.Monitor.

huangapple
  • 本文由 发表于 2023年6月19日 01:50:56
  • 转载请务必保留本文链接：https://go.coder-hub.com/76501866.html
  • c#
  • winapi
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