NAME
XAllocClassHint, XSetClassHint, XGetClassHint, XClassHint - allocate class hints
structure and set or read a window's WM_CLASS property
SYNTAX
XClassHint
*XAllocClassHint(void);
XSetClassHint(Display
* display, Window w, XClassHint *class_hints);
Status
XGetClassHint(Display * display, Window w, XClassHint
*class_hints_return);
ARGUMENTS
- display
- Specifies the connection to the X server.
- class_hints
- Specifies the XClassHint structure that is to be
used.
- class_hints_return
- Returns the XClassHint structure.
- w
- Specifies the window.
DESCRIPTION
The
XAllocClassHint function allocates and returns a pointer to a
XClassHint structure. Note that the pointer fields in the
XClassHint structure are initially set to NULL. If insufficient memory
is available,
XAllocClassHint returns NULL. To free the memory
allocated to this structure, use
XFree.
The
XSetClassHint function sets the class hint for the specified window.
If the strings are not in the Host Portable Character Encoding, the result is
implementation-dependent.
XSetClassHint can generate
BadAlloc and
BadWindow errors.
The
XGetClassHint function returns the class hint of the specified window
to the members of the supplied structure. If the data returned by the server
is in the Latin Portable Character Encoding, then the returned strings are in
the Host Portable Character Encoding. Otherwise, the result is
implementation-dependent. It returns a nonzero status on success; otherwise,
it returns a zero status. To free res_name and res_class when finished with
the strings, use
XFree on each individually.
XGetClassHint can generate a
BadWindow error.
PROPERTIES
- WM_CLASS
- Set by application programs to allow window and session
managers to obtain the application's resources from the resource
database.
STRUCTURES
The
XClassHint structure contains:
typedef struct {
char *res_name;
char *res_class;
} XClassHint;
The res_name member contains the application name,
and the res_class member contains the application class.
Note that the name set in this property may differ from the name set as WM_NAME.
That is, WM_NAME specifies what should be displayed in the title bar and,
therefore, can contain temporal information (for example, the name of
a file currently in an editor's buffer).
On the other hand,
the name specified as part of WM_CLASS is the formal name of the application
that should be used when retrieving the application's resources from the
resource database.
DIAGNOSTICS
- BadAlloc
- The server failed to allocate the requested resource or
server memory.
- BadWindow
- A value for a Window argument does not name a defined
Window.
SEE ALSO
XAllocIconSize(3), XAllocSizeHints(3), XAllocWMHints(3), XFree(3),
XSetCommand(3), XSetTransientForHint(3), XSetTextProperty(3),
XSetWMClientMachine(3), XSetWMColormapWindows(3), XSetWMIconName(3),
XSetWMName(3), XSetWMProperties(3), XSetWMProtocols(3),
XStringListToTextProperty(3)
Xlib - C Language X Interface