RegSetValueEx (Windows CE 5.0)

Article
09/14/2012

This function stores data in the value field of an open registry key. It can also set additional value and type information for the specified key.

A remote application interface (RAPI) version of this function exists, and it is called CeRegSetValueEx (RAPI).

LONGRegSetValueEx( HKEYhKey, LPCWSTRlpValueName, DWORDReserved, DWORDdwType, constBYTE* lpData, DWORDcbData );

Parameters

hKey
[in] Handle to a currently 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 containing the name of the value to set. If a value with this name is not already present in the key, the function adds it to the key. If this parameter is NULL or an empty string, the function sets the type and data for the key's unnamed value. Registry keys do not have default values, but they can have one unnamed value, which can be of any type. The maximum length of a value name is 255, not including the terminating NULL character.
Reserved
[in] Reserved; must be zero.

dwType
[in] Type of information to be stored as the value's data. The following table shows the possible values for dwType.

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 multi-byte 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) in little-endian format.
REG_DWORD_BIG_ENDIAN	Specifies a 32-bit number in big-endian format. In big-endian format, a multi-byte 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) in big-endian format.
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	No defined value type.
REG_RESOURCE_LIST	Specifies a device-driver resource list.
REG_SZ	Specifies a null-terminated Unicode string. Do not use the REG_SZ type to store hard-coded paths to the system root.

lpData
[in] Pointer to a buffer containing the data to be stored with the specified value name.
cbData
[in] Size, in bytes, of the information pointed to by the lpData parameter. If the data is of type REG_SZ, REG_EXPAND_SZ, or REG_MULTI_SZ, cbData must include the size of the terminating null character. The maximum size of data allowed in Windows CE is 4 KB.

Return Values

ERROR_SUCCESS indicates success. A nonzero error code defined in Winerror.h indicates failure. To get a generic description of the error, call FormatMessage with the FORMAT_MESSAGE_FROM_SYSTEM flag set. The message resource is optional; therefore, if you call FormatMessage it could fail.

Remarks

Value lengths are limited by available memory. Long values (more than 2048 bytes) should be stored as files with the filenames stored in the registry. This helps the registry perform efficiently. Application elements such as icons, bitmaps, and executable files should be stored as files and not be placed in the registry.

Windows CE supports only the Unicode version of this function.

Windows Mobile Remarks

If RegSetValueEx is used to change a value, but the new value is the same as the previous value, no notification is returned.

Requirements

OS Versions: Windows CE 1.0 and later.
Header: Winreg.h.
Link Library: Coredll.lib.

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