Provided by: libx11-doc_1.6.9-2ubuntu1_all bug


       XAllocClassHint, XSetClassHint, XGetClassHint, XClassHint - allocate class hints structure
       and set or read a window's WM_CLASS property


       XClassHint *XAllocClassHint(void);

       XSetClassHint(Display *display, Window w, XClassHint *class_hints);

       Status XGetClassHint(Display *display, Window w, XClassHint *class_hints_return);


       display   Specifies the connection to the X server.

                 Specifies the XClassHint structure that is to be used.

                 Returns the XClassHint structure.

       w         Specifies the window.


       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.


       WM_CLASS  Set  by  application programs to allow window and session managers to obtain the
                 application's resources from the resource database.


       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.


       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.


       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