DWORD

DWORD, short for double word, is a data type used in Windows programming to store a 32-bit unsigned integer. The term double word comes from the historical convention that a word is 16 bits, so a double word is 32 bits.

In Windows header files such as Windef.h or WinNT.h, DWORD is defined as typedef unsigned long DWORD. On modern Windows platforms, including 64-bit editions, DWORD remains 32 bits long because Windows uses the LLP64 model where long is 32 bits. The numeric range is 0 through 4294967295.

DWORD is widely used in the Windows API to hold counts, sizes, bit flags, and identifiers. It is commonly seen as parameters to functions, fields in structures, and return values. It often represents IDs and non-pointer values rather than handles or objects.

Related types include WORD, which is 16-bit unsigned, and BYTE, which is 8-bit. For larger values, Windows provides types such as DWORDLONG or ULONGLONG (64-bit) and pointer-sized variants like DWORD_PTR, which adapt to the target architecture.

Examples of usage include representing ARGB color values in graphics APIs, numeric IDs, and flag sets in various API calls. The exact in-memory representation of a DWORD follows standard unsigned integer conventions; on Windows x86 systems it is stored in little-endian order, but the logical value is independent of endianness for typical programming tasks.