Public Member Functions | List of all members
BClipboard Class Reference

Used for short-term data storage between documents and applications via copy and paste operations. More...

Public Member Functions

 BClipboard (const char *name, bool transient=false)
 Create a BClipboard object with the given name. More...
 
virtual ~BClipboard ()
 Destroys the BClipboard object. The clipboard data is not destroyed. More...
 
const char * Name () const
 Returns the name of the BClipboard object. More...
 
Commit Count
uint32 LocalCount () const
 Returns the (locally cached) number of commits to the clipboard. More...
 
uint32 SystemCount () const
 Returns the number of commits to the clipboard. More...
 
Monitoring
status_t StartWatching (BMessenger target)
 Start watching the BClipboard object for changes. More...
 
status_t StopWatching (BMessenger target)
 Stop watching the BClipboard object for changes. More...
 
Locking
bool Lock ()
 Locks the clipboard so that no other tread can read from it or write to it. More...
 
void Unlock ()
 Unlocks the clipboard. More...
 
bool IsLocked () const
 Returns whether or not the clipboard is locked. More...
 
Clipboard Data Transaction
status_t Clear ()
 Clears out all data from the clipboard. More...
 
status_t Commit ()
 Commits the clipboard data to the BClipboard object. More...
 
status_t Commit (bool failIfChanged)
 Commits the clipboard data to the BClipboard object with the option to fail if there is a change to the clipboard data. More...
 
status_t Revert ()
 Reverts the clipboard data. More...
 
Clipboard Data Message
BMessenger DataSource () const
 Gets a BMessenger object targeting the application that last modified the clipboard. More...
 
BMessageData () const
 Gets a pointer to the BMessage object that holds the clipboard data. More...
 

Detailed Description

Used for short-term data storage between documents and applications via copy and paste operations.

Clipboards are differentiated by their name. In order for two applications to share a clipboard they simply have to create a BClipboard object with the same name. However, it is rarely necessary to create your own clipboard, instead you can use the be_clipboard system clipboard object.

Remarks
To access the system clipboard without a BApplication object, create a BClipboard object with the name "system". You should avoid creating a custom clipboard with the name "system" for your own use.

To access the clipboard data call the Data() method. The BMessage object returned by the Data() method has the following properties:

To read and write to the clipboard you must first lock the BClipboard object. If you fail to lock the BClipboard object then the Data() method will return NULL instead of a pointer to a BMessage object.

Below is an example of reading a string from the system clipboard.

const char *string;
int32 stringLen;
if (be_clipboard->Lock()) {
// Get the clipboard BMessage
// Read the string from the clipboard data message
clip->FindData("text/plain", B_MIME_TYPE, (const void **)&string,
&stringLen);
} else
fprintf(stderr, "could not lock clipboard.\n");

Below is an example of writing a string to the system clipboard.

const char* string = "Some clipboard data";
if (be_clipboard->Lock()) {
// Clear the clipboard data
// Get the clipboard data message
// Write string data to the clipboard data message
clip->AddData("text/plain", B_MIME_TYPE, string, strlen(string));
// Commit the data to the clipboard
status = be_clipboard->Commit();
if (status != B_OK)
fprintf(stderr, "could not commit data to clipboard.\n");
} else
fprintf(stderr, "could not lock clipboard.\n");
Since
BeOS R3

Constructor & Destructor Documentation

◆ BClipboard()

BClipboard::BClipboard ( const char *  name,
bool  transient = false 
)

Create a BClipboard object with the given name.

If the name parameter is NULL then the "system" BClipboard object is constructed instead.

Parameters
nameThe name of the clipboard.
transientIf true, lose data after a reboot (currently unused).
Since
BeOS R3

◆ ~BClipboard()

BClipboard::~BClipboard ( )
virtual

Destroys the BClipboard object. The clipboard data is not destroyed.

Since
BeOS R3

Member Function Documentation

◆ Clear()

status_t BClipboard::Clear ( )

Clears out all data from the clipboard.

You should call Clear() before adding new data to the BClipboard object.

Returns
A status code.
Return values
B_OKEverything went find.
B_NOT_ALLOWEDThe clipboard is not locked.
B_NO_MEMORYRan out of memory initializing the data message.
B_ERRORAnother error occurred.
Since
BeOS R3

◆ Commit() [1/2]

status_t BClipboard::Commit ( )

Commits the clipboard data to the BClipboard object.

Returns
A status code.
Return values
B_OKEverything went find.
B_NOT_ALLOWEDThe clipboard is not locked.
B_ERRORAnother error occurred.
Since
BeOS R3

◆ Commit() [2/2]

status_t BClipboard::Commit ( bool  failIfChanged)

Commits the clipboard data to the BClipboard object with the option to fail if there is a change to the clipboard data.

Parameters
failIfChangedWhether or not to fail to commit the changes if there is a change in the clipboard data.
Returns
A status code.
Return values
B_OKEverything went find.
B_NOT_ALLOWEDThe clipboard is not locked.
B_ERRORAnother error occurred.
Since
BeOS R5

◆ Data()

BMessage * BClipboard::Data ( ) const

Gets a pointer to the BMessage object that holds the clipboard data.

If the BClipboard object is not locked this method returns NULL.

Returns
A pointer to the BMessage object that holds the clipboard data or NULL if the clipboard is not locked.
Since
BeOS R3

◆ DataSource()

BMessenger BClipboard::DataSource ( ) const

Gets a BMessenger object targeting the application that last modified the clipboard.

The clipboard object does not need to be locked to call this method.

Returns
A BMessenger object that targets the application that last modified the clipboard.
Since
BeOS R3

◆ IsLocked()

bool BClipboard::IsLocked ( ) const

Returns whether or not the clipboard is locked.

Returns
true if the clipboard is locked, false if it is unlocked.
Since
BeOS R5

◆ LocalCount()

uint32 BClipboard::LocalCount ( ) const

Returns the (locally cached) number of commits to the clipboard.

The returned value is the number of successful Commit() invocations for the clipboard represented by this object, either invoked on this object or another (even from another application). This method returns a locally cached value, which might already be obsolete. For an up-to-date value use SystemCount().

Returns
The number of commits to the clipboard.
See also
SystemCount()
Since
BeOS R5

◆ Lock()

bool BClipboard::Lock ( )

Locks the clipboard so that no other tread can read from it or write to it.

You should call Lock() before reading or writing to the clipboard.

Returns
true if the clipboard was locked, false otherwise.
See also
Unlock()
Since
BeOS R3

◆ Name()

const char * BClipboard::Name ( ) const

Returns the name of the BClipboard object.

Returns
The name of the clipboard.
Since
BeOS R3

◆ Revert()

status_t BClipboard::Revert ( )

Reverts the clipboard data.

The method should be used in the case that you have made a change to the clipboard data message and then decide to revert the change instead of committing it.

Returns
A status code.
Return values
B_OKEverything went find.
B_NOT_ALLOWEDThe clipboard is not locked.
B_NO_MEMORYRan out of memory initializing the data message.
B_ERRORAnother error occurred.
Since
BeOS R5

◆ StartWatching()

status_t BClipboard::StartWatching ( BMessenger  target)

Start watching the BClipboard object for changes.

When a change in the clipboard occurs, most like as the result of a cut or copy action, a B_CLIPBOARD_CHANGED message is sent to target.

Return values
B_OKEverything went fine.
B_BAD_VALUEtarget is invalid.
B_ERRORAn error occured.
See also
StopWatching()
Since
BeOS R5

◆ StopWatching()

status_t BClipboard::StopWatching ( BMessenger  target)

Stop watching the BClipboard object for changes.

Return values
B_OKEverything went fine.
B_BAD_VALUEtarget is invalid.
B_ERRORAn error occurred.
See also
StartWatching()
Since
BeOS R5

◆ SystemCount()

uint32 BClipboard::SystemCount ( ) const

Returns the number of commits to the clipboard.

The returned value is the number of successful Commit() invocations for the clipboard represented by this object, either invoked on this object or another (even from another application). This method retrieves the value directly from the system service managing the clipboards, so it is more expensive, but more up-to-date than LocalCount(), which returns a locally cached value.

Returns
The number of commits to the clipboard.
See also
LocalCount()
Since
BeOS R5

◆ Unlock()

void BClipboard::Unlock ( )

Unlocks the clipboard.

See also
Lock()
Since
BeOS R3