XAllocClassHint(3)

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 avail-
       able, XAllocClassHint returns NULL.  To free the memory allocated to
       this structure, use XFree.

       The XSetClassHint function sets the class hint for the specified win-
       dow.  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 win-
       dow 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.  Other-
       wise, 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 man-
                 agers 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(3X11), XAllocSizeHints(3X11), XAllocWMHints(3X11),
       XFree(3X11), XSetCommand(3X11), XSetTransientForHint(3X11), XSet-
       TextProperty(3X11), XSetWMClientMachine(3X11), XSetWMColormapWin-
       dows(3X11), XSetWMIconName(3X11), XSetWMName(3X11), XSetWMProper-
       ties(3X11), XSetWMProtocols(3X11), XStringListToTextProperty(3X11)
       Xlib - C Language X Interface

X Version 11                     libX11 1.1.1               XAllocClassHint(3)