UIntPtr

UIntPtr is a value type in the System namespace that represents a pointer-sized unsigned integer. It is designed to hold values that are pointers or handles obtained from unmanaged code and treated as addresses rather than numeric quantities. The size of a UIntPtr value matches the native pointer size of the current platform: 4 bytes on 32-bit processes and 8 bytes on 64-bit processes.

Constructors and conversion: You can construct a UIntPtr from unsigned integral values, such as uint or ulong. In unsafe code, a void* can be converted to a UIntPtr. Arithmetic is not defined directly for UIntPtr; to perform arithmetic, convert to a larger unsigned integer type (such as ulong), operate, and convert back. UIntPtr provides methods to convert to unsigned integer types, such as ToUInt64 and ToUInt32, depending on the platform size. The static field UIntPtr.Zero represents a zero value.

Usage and purpose: UIntPtr is commonly used in interop scenarios and unsafe code when an unsigned, pointer-sized value is required to hold a native address or a handle returned by unmanaged APIs. It serves as the unsigned counterpart to IntPtr, which is signed. In practice, the choice between UIntPtr and IntPtr depends on the API contract and whether unsigned semantics are necessary. Some APIs and libraries expect an unsigned pointer-sized value, while others expect signed pointer-sized values.

Interoperability considerations: For many P/Invoke scenarios and marshalling tasks, IntPtr is more widely supported and understood by the .NET runtime and base libraries. UIntPtr can be appropriate when you specifically need unsigned semantics, but it may require explicit conversions and careful handling to avoid data loss on platform transitions or across APIs that expect signed values.

See also: IntPtr, Pointer, P/Invoke, Marshal, unsafe.