xcb_intern_atom_unchecked(3)

Usage

#include <xcb/xproto.h>

Request function

xcb_intern_atom_cookie_t xcb_intern_atom(xcb_connection_t *conn, uint8_t only_if_exists, uint16_t name_len, const char *name);

Reply datastructure

typedef struct xcb_intern_atom_reply_t {
    uint8_t    response_type;
    uint8_t    pad0;
    uint16_t   sequence;
    uint32_t   length;
    xcb_atom_t atom;
} xcb_intern_atom_reply_t;

Reply function

xcb_intern_atom_reply_t *xcb_intern_atom_reply(xcb_connection_t *conn, xcb_intern_atom_cookie_t cookie, xcb_generic_error_t **e);

Request arguments

`conn`	The XCB connection to X11.
`only_if_exists`	Return a valid atom id only if the atom already exists.
`name_len`	The length of the following name.
`name`	The name of the atom.

Reply fields

response_type: The type of this reply, in this case XCB_INTERN_ATOM. This field is also present in the xcb_generic_reply_t and can be used to tell replies apart from each other.

sequence: The sequence number of the last request processed by the X11 server.

length: The length of the reply, in words (a word is 4 bytes).

atom: TODO: NOT YET DOCUMENTED.

Overview

Retrieves the identifier (xcb_atom_t TODO) for the atom with the specified name. Atoms are used in protocols like EWMH, for example to store window titles (_NET_WM_NAME atom) as property of a window.

If only_if_exists is 0, the atom will be created if it does not already exist. If only_if_exists is 1, XCB_ATOM_NONE will be returned if the atom does not yet exist.

Return value

Returns an xcb_intern_atom_cookie_t. Errors have to be handled when calling the reply function xcb_intern_atom_reply.

If you want to handle errors in the event loop instead, use xcb_intern_atom_unchecked. See xcb-requests(3) for details.

Errors

`xcb_alloc_error_t`	TODO: reasons?
`xcb_value_error_t`	A value other than 0 or 1 was specified for only_if_exists.

Examples

/*
 * Resolves the _NET_WM_NAME atom.
 *
 */
void my_example(xcb_connection_t *c) {
    xcb_intern_atom_cookie_t cookie;
    xcb_intern_atom_reply_t *reply;
    cookie = xcb_intern_atom(c, 0, strlen("_NET_WM_NAME"), "_NET_WM_NAME");
    /* ... do other work here if possible ... */
    if ((reply = xcb_intern_atom_reply(c, cookie, NULL))) {
        printf("The _NET_WM_NAME atom has ID %u0, reply->atom);
        free(reply);
    }
}

Releases

6 releases since Debian 9 (Stretch); the text changed 4 times.