According to MSDN:
http://msdn.microsoft.com/en-gb/library/system.intptr(v=vs.100).aspx
It is merely a representation of "a pointer or a handle."
I have been doing some reading on how the IntPtr
is handled differently by the GC than other managed types, and I have not found any documentation or articles stating the IntPtr
is collected any differently, i.e., as soon as the IntPtr
goes out of scope it can be GC'd.
About why there is no use of the unsafe
keyword read the accepted answer especially the update:
Does unsafe code have any effect on safe code?
unsafe
has already been specified in the implementation of IntPtr
(see the field declarations in the IntPtr
implementation below), so the class using the IntPtr
does not have to mark any use of IntPtr
it uses as unsafe
also, otherwise it would be cascaded all the way up to other classes that might use types that have unsafe code in their implementation.
Besides the unsafe
code is not IntPtr
, it is the field private unsafe void* m_value;
that is unsafe
and you are not using it directly.
// Type: System.IntPtr
// Assembly: mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
// Assembly location: C:\Windows\Microsoft.NET\Framework\v4.0.30319\mscorlib.dll
using System.Globalization;
using System.Runtime;
using System.Runtime.ConstrainedExecution;
using System.Runtime.InteropServices;
using System.Runtime.Serialization;
using System.Security;
namespace System
{
[ComVisible(true)]
[__DynamicallyInvokable]
[Serializable]
public struct IntPtr : ISerializable
{
[SecurityCritical]
private unsafe void* m_value;
public static readonly IntPtr Zero;
[__DynamicallyInvokable]
public static int Size
{
[ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success), TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries"), __DynamicallyInvokable] get
{
return 4;
}
}
[SecuritySafeCritical]
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
[ReliabilityContract(Consistency.MayCorruptInstance, Cer.MayFail)]
[__DynamicallyInvokable]
public IntPtr(int value)
{
this.m_value = (void*) value;
}
[SecuritySafeCritical]
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
[ReliabilityContract(Consistency.MayCorruptInstance, Cer.MayFail)]
[__DynamicallyInvokable]
public IntPtr(long value)
{
this.m_value = (void*) checked ((int) value);
}
[ReliabilityContract(Consistency.MayCorruptInstance, Cer.MayFail)]
[SecurityCritical]
[CLSCompliant(false)]
[TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]
public IntPtr(void* value)
{
this.m_value = value;
}
[SecurityCritical]
private IntPtr(SerializationInfo info, StreamingContext context)
{
long int64 = info.GetInt64("value");
if (IntPtr.Size == 4 && (int64 > (long) int.MaxValue || int64 < (long) int.MinValue))
throw new ArgumentException(Environment.GetResourceString("Serialization_InvalidPtrValue"));
this.m_value = (void*) int64;
}
[ReliabilityContract(Consistency.MayCorruptInstance, Cer.MayFail)]
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
public static explicit operator IntPtr(int value)
{
return new IntPtr(value);
}
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
[ReliabilityContract(Consistency.MayCorruptInstance, Cer.MayFail)]
public static explicit operator IntPtr(long value)
{
return new IntPtr(value);
}
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
[ReliabilityContract(Consistency.MayCorruptInstance, Cer.MayFail)]
[SecurityCritical]
[CLSCompliant(false)]
public static explicit operator IntPtr(void* value)
{
return new IntPtr(value);
}
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
[SecuritySafeCritical]
[CLSCompliant(false)]
public static explicit operator void*(IntPtr value)
{
return value.ToPointer();
}
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
[SecuritySafeCritical]
public static explicit operator int(IntPtr value)
{
return (int) value.m_value;
}
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
[SecuritySafeCritical]
public static explicit operator long(IntPtr value)
{
return (long) (int) value.m_value;
}
[SecuritySafeCritical]
[ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
public static bool operator ==(IntPtr value1, IntPtr value2)
{
return value1.m_value == value2.m_value;
}
[ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
[SecuritySafeCritical]
public static bool operator !=(IntPtr value1, IntPtr value2)
{
return value1.m_value != value2.m_value;
}
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
[ReliabilityContract(Consistency.MayCorruptInstance, Cer.MayFail)]
public static IntPtr operator +(IntPtr pointer, int offset)
{
return new IntPtr(pointer.ToInt32() + offset);
}
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
[ReliabilityContract(Consistency.MayCorruptInstance, Cer.MayFail)]
public static IntPtr operator -(IntPtr pointer, int offset)
{
return new IntPtr(pointer.ToInt32() - offset);
}
[ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
[SecuritySafeCritical]
internal unsafe bool IsNull()
{
return (IntPtr) this.m_value == IntPtr.Zero;
}
[SecurityCritical]
unsafe void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context)
{
if (info == null)
throw new ArgumentNullException("info");
info.AddValue("value", (long) (int) this.m_value);
}
[SecuritySafeCritical]
[__DynamicallyInvokable]
public override unsafe bool Equals(object obj)
{
if (obj is IntPtr)
return this.m_value == ((IntPtr) obj).m_value;
else
return false;
}
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
[SecuritySafeCritical]
[__DynamicallyInvokable]
public override unsafe int GetHashCode()
{
return (int) this.m_value;
}
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
[SecuritySafeCritical]
[ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
[__DynamicallyInvokable]
public unsafe int ToInt32()
{
return (int) this.m_value;
}
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
[SecuritySafeCritical]
[ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
[__DynamicallyInvokable]
public unsafe long ToInt64()
{
return (long) (int) this.m_value;
}
[SecuritySafeCritical]
[__DynamicallyInvokable]
public override unsafe string ToString()
{
return ((int) this.m_value).ToString((IFormatProvider) CultureInfo.InvariantCulture);
}
[SecuritySafeCritical]
[__DynamicallyInvokable]
public unsafe string ToString(string format)
{
return ((int) this.m_value).ToString(format, (IFormatProvider) CultureInfo.InvariantCulture);
}
[ReliabilityContract(Consistency.MayCorruptInstance, Cer.MayFail)]
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
public static IntPtr Add(IntPtr pointer, int offset)
{
return pointer + offset;
}
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
[ReliabilityContract(Consistency.MayCorruptInstance, Cer.MayFail)]
public static IntPtr Subtract(IntPtr pointer, int offset)
{
return pointer - offset;
}
[SecuritySafeCritical]
[CLSCompliant(false)]
[ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
[TargetedPatchingOptOut("Performance critical to inline across NGen image boundaries")]
public unsafe void* ToPointer()
{
return this.m_value;
}
}
}