configure: add '-Wundef' to warning flags
[lttng-tools.git] / src / common / fd-handle.h
1 /*
2 * Copyright (C) 2020 Jérémie Galarneau <jeremie.galarneau@efficios.com>
3 *
4 * SPDX-License-Identifier: LGPL-2.1-only
5 *
6 */
7
8 #ifndef FD_HANDLE_H
9 #define FD_HANDLE_H
10
11 #include <common/macros.h>
12
13 /*
14 * Wrapper around a file descriptor providing reference counting semantics.
15 *
16 * An fd_handle will close() the underlying file descriptor when its reference
17 * count reaches zero.
18 */
19 struct fd_handle;
20
21 /* Create a file descriptor handle. */
22 struct fd_handle *fd_handle_create(int fd);
23
24 /* Acquire reference to a file descriptor handle. */
25 void fd_handle_get(struct fd_handle *handle);
26
27 /* Release reference to a file descriptor handle. */
28 void fd_handle_put(struct fd_handle *handle);
29
30 /*
31 * Return the underlying file descriptor of a file descriptor handle.
32 *
33 * This function can't fail.
34 */
35 int fd_handle_get_fd(struct fd_handle *handle);
36
37 /*
38 * Obtain a copy of a file descriptor handle.
39 *
40 * On success, the caller becomes the sole owner of the returned file descriptor
41 * handle. The underlying file descriptor is duplicated using dup(). Refer to
42 * the system documentation for the semantics of dup() for this particular file
43 * descriptor type.
44 */
45 struct fd_handle *fd_handle_copy(const struct fd_handle *handle);
46
47 #endif /* FS_HANDLE_H */
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