XAllocClassHint(3X)                           XAllocClassHint(3X)



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

SYNOPSIS
     XClassHint *XAllocClassHint()

     XSetClassHint(display, w, class-hints)
     Display *display;
     Window w;
     XClassHint *class-hints;

     Status XGetClassHint(display, w, class-hints-return)
     Display *display;
     Window w;
     XClassHint *class-hints-return;

DESCRIPTION
     The XAllocClassHint function allocates and returns a pointer
     to a XClassHint structure.  Note that the pointer members of
     the XClassHint structure are initially set to NULL.  If in-
     sufficient 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.

     The XGetClassHint function returns the class of the speci-
     fied window.  To free res_name and res_class (described
     below) when finished with the strings, use XFree.

   Arguments
     These functions accept the following 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.

   Properties
     These functions use the following property:

     WM_CLASS
             Set by client application to allow window and ses-



November, 1990                                                  1

XAllocClassHint(3X)                           XAllocClassHint(3X)



             sion managers to obtain the application's resources
             from the resource database.

   Structures
     The XClassHint structure is defined as follows.

     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 tem-
     poral information (for example, the name of a file currently
     in an editor's buffer).  On the other hand, the name speci-
     fied as part of WM_CLASS is the formal name of the applica-
     tion that should be used when retrieving the application's
     resources from the resource database.

ERRORS
     BadAlloc
             The server failed to allocate the requested resource
             or server memory.

     BadWindow
             A value for a Window argument does not name a de-
             fined Window.

     The XSetClassHint function can generate BadAlloc and BadWin-
     dow errors.

     The XGetClassHint function can generate a BadWindow error.

SEE ALSO
     XAllocIconSize(3X), XAllocSizeHints(3X), XAllocWMHints(3X),
     XFree(3X), XSetCommand(3X), XSetTransientForHint(3X),
     XSetTextProperty(3X), XSetWMClientMachine(3X),
     XSetWMColormapWindows(3X), XSetWMIconName(3X),
     XSetWMName(3X), XSetWMProperties(3X), XSetWMProtocols(3X),
     XStringListToTextProperty(3X)

     Xlib - C Language Interface











2                                                  November, 1990