NKRegQueryValueExW (Compact 2013)

10/16/2014

This function retrieves the type and data for a specified value name associated with an open registry key.

Syntax

LONG NKRegQueryValueExW(
  HKEY hKey, 
  LPCWSTR lpValueName, 
  LPDWORD lpReserved, 
  LPDWORD lpType, 
  LPBYTE lpData, 
  LPDWORD lpcbData
);

Parameters

• hKey
  [in] Handle to an open key or any of the following predefined reserved handle values:

  • HKEY_CLASSES_ROOT
  • HKEY_CURRENT_USER
  • HKEY_LOCAL_MACHINE
  • HKEY_USERS

• lpValueName
  [in] Pointer to a string that contains the name of the value to query.

  If this parameter is NULL or an empty string, the function retrieves the type and data for the key's unnamed value.

  A registry key does not automatically have an unnamed or default value.

  Unnamed values can be of any type.

• lpReserved
  [in] Reserved; set to NULL.

• lpType
  [out] Pointer to a variable that receives the type of data associated with the specified value.

  The following table shows the possible values that lpType can return.

  Value	Description
  REG_BINARY	Specifies binary data in any form.
  REG_DWORD	Specifies a 32-bit number.
  REG_DWORD_LITTLE_ENDIAN	Specifies a 32-bit number in little-endian format. This is equivalent to REG_DWORD. In little-endian format, a multibyte value is stored in memory from the lowest byte (the little end) to the highest byte. For example, the value 0x12345678 is stored as (0x78 0x56 0x34 0x12).
  REG_DWORD_BIG_ENDIAN	Specifies a 32-bit number in big-endian format. In big-endian format, a multibyte value is stored in memory from the highest byte (the big end) to the lowest byte. For example, the value 0x12345678 is stored as (0x12 0x34 0x56 0x78).
  REG_EXPAND_SZ	Specifies a null-terminated string that contains unexpanded references to environment variables (for example, %PATH%).
  REG_LINK	Specifies a Unicode symbolic link. Used internally; applications should not use this type.
  REG_MULTI_SZ	Specifies an array of null-terminated strings, terminated by two null characters.
  REG_NONE	Specifies no defined value type.
  REG_RESOURCE_LIST	Specifies a device-driver resource list.
  REG_SZ	Specifies a null-terminated Unicode string.

  The lpType parameter can be NULL if the type is not required.

• lpData
  [out] Pointer to a buffer that receives the value's data.

  This parameter can be set to NULL if the data is not required.

• lpcbData
  [in, out] Pointer to a variable that specifies the size, in bytes, of the buffer that lpData points to. When the function returns, this variable contains the size of the data copied to lpData.

  If the data has the REG_SZ, REG_MULTI_SZ, or REG_EXPAND_SZ type, lpcbData also includes the size of the terminating null character.

  The lpcbData parameter can be NULL only if lpData is NULL.

  If the buffer that the lpData parameter specifies is not large enough to hold the data, the function returns the value ERROR_MORE_DATA, and stores the required buffer size, in bytes, in the variable that lpcbData points to.

  If lpData is set to NULL, and lpcbData is set to a non-NULL value, the function returns ERROR_SUCCESS, and stores the size of the data, in bytes, in the variable that lpcbData points to. This enables an application to determine the best way to allocate a buffer for the value's data.

Return Value

The following table shows the possible return values.

Value	Description
ERROR_SUCCESS	Success.
ERROR_MORE_DATA	More data is available.
ERROR_NOT_READY	Registry is not ready.

The function may return other standard error codes defined in Winerror.h, as appropriate.

Remarks

This function is only available for use by the OAL. The pfnRegQueryValueExW member of NKGLOBAL points to this function.

Requirements

Header	pkfuncs.h
Library	coredll.lib

See Also

Reference

Kernel Functions Available to the OAL
NKRegCreateKeyExW
NKRegOpenKeyExW
NKRegCloseKey
NKRegSetValueExW