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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