Newsgroup: it.comp.programmare.win32
Titolo: Recuperare un valore del Registry

Sto imparando a programmare con le api32 e vorrei recuperare il valore che
sta dentro una chiave sotto forma di stringa (ab), ovvero sta scritto nel
frame destro della finestra del regedit...
Coma posso fare a recuperarlo?
Ho provato con la RegOpenKey ma non riesco a recuperare il valore che sta
nel frame di destra...
Potete darmi un consiglio?
Ciao e grazie in anticipo!!!

Dall'help dell'SDK Windows:
The RegQueryValueEx function retrieves the type and data for a specified
value name associated with an open registry key.
LONG RegQueryValueEx(
    HKEY hKey, // handle of key to query
    LPTSTR lpValueName, // address of name of value to query
    LPDWORD lpReserved, // reserved
    LPDWORD lpType, // address of buffer for value type
    LPBYTE lpData, // address of data buffer
    LPDWORD lpcbData  // address of data buffer size
   );
Parameters
hKey
Identifies 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
Points to a null-terminated string containing the name of the value to be
queried.
lpReserved
Reserved; must be NULL.
lpType
Points to a variable that receives the key's value type. The value returned
through this parameter will be one of the following:
Value Meaning
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 (same as
REG_DWORD). In little-endian format, the most significant byte of a word is
the high-order byte. This is the most common format for computers running
Windows NT and Windows 95.
REG_DWORD_BIG_ENDIAN A 32-bit number in big-endian format. In big-endian
format, the most significant byte of a word is the low-order byte.
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.
REG_LINK A Unicode symbolic link.
REG_MULTI_SZ An array of null-terminated strings, terminated by two null
characters.
REG_NONE No defined value type.
REG_RESOURCE_LIST A device-driver resource list.
REG_SZ A null-terminated string. It will be a Unicode or ANSI string
depending on whether you use the Unicode or ANSI functions.
The lpType parameter can be NULL if the type is not required.
lpData
Points to a buffer that receives the value's data. This parameter can be
NULL if the data is not required.
lpcbData
Points to a variable that specifies the size, in bytes, of the buffer
pointed to by the lpData parameter. When the function returns, this variable
contains the size of the data copied to lpData.
If the buffer specified by lpData parameter is not large enough to hold the
data, the function returns the value ERROR_MORE_DATA, and stores the
required buffer size, in bytes, into the variable pointed to by lpcbData.
If lpData is NULL, and lpcbData is non-NULL, the function returns
ERROR_SUCCESS, and stores the size of the data, in bytes, in the variable
pointed to by lpcbData. This lets an application determine the best way to
allocate a buffer for the value key's data.
If the data has the REG_SZ, REG_MULTI_SZ or REG_EXPAND_SZ type, then lpData
will also include the size of the terminating null character.
The lpcbData parameter can be NULL only if lpData is NULL.
Return Values
If the function succeeds, the return value is ERROR_SUCCESS.
If the function fails, the return value is a nonzero error code defined in
WINERROR.H. You can use the FormatMessage function with the
FORMAT_MESSAGE_FROM_SYSTEM flag to get a generic description of the error.
Remarks
The key identified by hKey must have been opened with KEY_QUERY_VALUE
access. To open the key, use the RegCreateKeyEx or RegOpenKeyEx function.
This function does not expand the environment-variable names in the value
data when the value type is REG_EXPAND_SZ. The ExpandEnvironmentStrings
function can be used to expand the environment-variable names.
If the value data has the REG_SZ, REG_MULTI_SZ or REG_EXPAND_SZ type, and
the ANSI version of this function is used (either by explicitly calling
RegQueryValueEx or by not defining Unicode before including the WINDOWS.H
file), this function converts the stored Unicode string to an ANSI string
before copying it to the buffer pointed to by lpData.
When calling the RegQueryValueEx function with hKey set to the
HKEY_PERFORMANCE_DATA handle and a value string of a specified object, the
returned data structure sometimes has unrequested objects. Don't be
surprised; this is normal behavior. When calling the RegQueryValueEx
function, you should always expect to walk the returned data structure to
look for the requested object.