.TH xcb_change_property 3  "libxcb 1.14" "X Version 11" "XCB Requests"
.ad l
.SH NAME
xcb_change_property \- Changes a window property
.SH SYNOPSIS
.hy 0
.B #include <xcb/xproto.h>
.SS Request function
.HP
xcb_void_cookie_t \fBxcb_change_property\fP(xcb_connection_t\ *\fIconn\fP, uint8_t\ \fImode\fP, xcb_window_t\ \fIwindow\fP, xcb_atom_t\ \fIproperty\fP, xcb_atom_t\ \fItype\fP, uint8_t\ \fIformat\fP, uint32_t\ \fIdata_len\fP, const void\ *\fIdata\fP);
.br
.hy 1
.SH REQUEST ARGUMENTS
.IP \fIconn\fP 1i
The XCB connection to X11.
.IP \fImode\fP 1i
One of the following values:
.RS 1i
.IP \fIXCB_PROP_MODE_REPLACE\fP 1i
Discard the previous property value and store the new data.
.IP \fIXCB_PROP_MODE_PREPEND\fP 1i
Insert the new data before the beginning of existing data. The \fIformat\fP must
match existing property value. If the property is undefined, it is treated as
defined with the correct type and format with zero-length data.
.IP \fIXCB_PROP_MODE_APPEND\fP 1i
Insert the new data after the beginning of existing data. The \fIformat\fP must
match existing property value. If the property is undefined, it is treated as
defined with the correct type and format with zero-length data.
.RE
.RS 1i


.RE
.IP \fIwindow\fP 1i
The window whose property you want to change.
.IP \fIproperty\fP 1i
The property you want to change (an atom).
.IP \fItype\fP 1i
The type of the property you want to change (an atom).
.IP \fIformat\fP 1i
Specifies whether the data should be viewed as a list of 8-bit, 16-bit or
32-bit quantities. Possible values are 8, 16 and 32. This information allows
the X server to correctly perform byte-swap operations as necessary.
.IP \fIdata_len\fP 1i
Specifies the number of elements (see \fIformat\fP).
.IP \fIdata\fP 1i
The property data.
.SH DESCRIPTION
Sets or updates a property on the specified \fIwindow\fP. Properties are for
example the window title (\fIWM_NAME\fP) or its minimum size (\fIWM_NORMAL_HINTS\fP).
Protocols such as EWMH also use properties - for example EWMH defines the
window title, encoded as UTF-8 string, in the \fI_NET_WM_NAME\fP property.
.SH RETURN VALUE
Returns an \fIxcb_void_cookie_t\fP. Errors (if any) have to be handled in the event loop.

If you want to handle errors directly with \fIxcb_request_check\fP instead, use \fIxcb_change_property_checked\fP. See \fBxcb-requests(3)\fP for details.
.SH ERRORS
.IP \fIxcb_alloc_error_t\fP 1i
The X server could not store the property (no memory?).
.IP \fIxcb_atom_error_t\fP 1i
\fIproperty\fP or \fItype\fP do not refer to a valid atom.
.IP \fIxcb_match_error_t\fP 1i
TODO: reasons?
.IP \fIxcb_value_error_t\fP 1i
TODO: reasons?
.IP \fIxcb_window_error_t\fP 1i
The specified \fIwindow\fP does not exist.
.SH EXAMPLE
.nf
.sp
/*
 * Sets the WM_NAME property of the window to "XCB Example".
 *
 */
void my_example(xcb_connection_t *conn, xcb_window_t window) {
    xcb_change_property(conn,
        XCB_PROP_MODE_REPLACE,
        window,
        XCB_ATOM_WM_NAME,
        XCB_ATOM_STRING,
        8,
        strlen("XCB Example"),
        "XCB Example");
    xcb_flush(conn);
}
.fi
.SH SEE ALSO
.BR xcb-requests (3),
.BR xcb-examples (3),
.BR xcb_intern_atom (3),
.BR xprop (1)
.SH AUTHOR
Generated from xproto.xml. Contact xcb@lists.freedesktop.org for corrections and improvements.