GetValue

Inside Macintosh: OpenDoc Class Reference /: Part 1 - Classes and Methods / ODStorageUnit

GetValue
The GetValue method reads data from the currently focused value, starting at the offset (inclusive).
ODULong GetValue (in ODULong length,
                  out ODByteArray value);
length
The length (number of bytes) of data to read, expressed as an unsigned 32-bit value.
value
A byte array structure to contain the retrieved data.
return value
The number of bytes read, expressed as an unsigned 32-bit value.

DISCUSSION
You call this method to read data from the currently focused value. If that value is a promise value, the promise is fulfilled before the data is read. This method starts reading data at the current offset and stops after reading the number of bytes specified by the length parameter or after reaching the end of the data in the currently focused value, whichever comes first.
When you call this method, the _buffer field of the value output parameter should be kODNULL; if it isn't, the buffer to which that field points will not be deallocated.
This method sets the _buffer field of the value output parameter to point to a memory block containing the data that is read from the storage unit; it sets the _maximum field to the specified length and the _length field to the number of bytes actually read.
When you no longer need the structure you pass as the value parameter, you should deallocate that structure and its buffer.

EXCEPTIONS

kODErrUnfocusedStorageUnit
This storage unit is not focused on a value.
kODErrZeroRefCount
This storage unit has a reference count of 0.

SEE ALSO
The ODByteArray type (page 877).
The ODStorageUnit::GetSize method (page 695).
The ODStorageUnit::SetValue method (page 714).
"Manipulating the Data in a Value" on page 276 in OpenDoc Programmer's Guide.
"Creating Additional Storage Units" on page 301 in OpenDoc Programmer's Guide.