在Windows注册表操作的API中，如果参数有"__out_opt LPDWORD pdwType"，那么"pdwType"则是保存的为键值的类型。注册表中键值类型的分类：
| Value | Type |
|---|---|
| REG_BINARY | Binary data in any form. |
| REG_DWORD | A 32-bit number. |
| REG_DWORD_LITTLE_ENDIAN | A 32-bit number in little-endian format. Windows is designed to run on little-endian computer architectures. Therefore, this value is defined as REG_DWORD in the Windows header files. |
| REG_DWORD_BIG_ENDIAN | A 32-bit number in big-endian format. Some UNIX systems support big-endian architectures. |
| REG_EXPAND_SZ | A null-terminated string that contains unexpanded references to environment variables (for example, "%PATH%"). It will be a Unicode or ANSI string depending on whether you use the Unicode or ANSI functions. To expand the environment variable references, use the ExpandEnvironmentStrings function. |
| REG_LINK | Reserved for system use. |
| REG_MULTI_SZ | A sequence of null-terminated strings, terminated by an empty string (\0). The following is an example: String1\0String2\0String3\0LastString\0\0 The first \0 terminates the first string, the second to the last \0 terminates the last string, and the final \0 terminates the sequence. Note that the final terminator must be factored into the length of the string. |
| REG_NONE | No defined value type. |
| REG_QWORD | A 64-bit number. |
| REG_QWORD_LITTLE_ENDIAN | A 64-bit number in little-endian format. Windows is designed to run on little-endian computer architectures. Therefore, this value is defined as REG_QWORD in the Windows header files. |
| REG_SZ | A null-terminated string. This will be either a Unicode or an ANSI string, depending on whether you use the Unicode or ANSI functions. |
而表中第一列的宏的定义在源码头文件中定义如下：
//
//
// Predefined Value Types.
//
#define REG_NONE ( 0 ) // No value type
#define REG_SZ ( 1 ) // Unicode nul terminated string
#define REG_EXPAND_SZ ( 2 ) // Unicode nul terminated string
// (with environment variable references)
#define REG_BINARY ( 3 ) // Free form binary
#define REG_DWORD ( 4 ) // 32-bit number
#define REG_DWORD_LITTLE_ENDIAN ( 4 ) // 32-bit number (same as REG_DWORD)
#define REG_DWORD_BIG_ENDIAN ( 5 ) // 32-bit number
#define REG_LINK ( 6 ) // Symbolic Link (unicode)
#define REG_MULTI_SZ ( 7 ) // Multiple Unicode strings
#define REG_RESOURCE_LIST ( 8 ) // Resource list in the resource map
#define REG_FULL_RESOURCE_DESCRIPTOR ( 9 ) // Resource list in the hardware description
#define REG_RESOURCE_REQUIREMENTS_LIST ( 10 )
#define REG_QWORD ( 11 ) // 64-bit number
#define REG_QWORD_LITTLE_ENDIAN ( 11 ) // 64-bit number (same as REG_QWORD)
// end_wdm
注册表操作技巧请参考下面例子(主要是递归思想, 操作电脑中文件目录也是如此)：