i3
shmlog.h
Go to the documentation of this file.
1 /*
2  * vim:ts=4:sw=4:expandtab
3  *
4  * i3 - an improved dynamic tiling window manager
5  * © 2009-2012 Michael Stapelberg and contributors (see also: LICENSE)
6  *
7  * The format of the shmlog data structure which i3 development versions use by
8  * default (ringbuffer for storing the debug log).
9  *
10  */
11 #pragma once
12 
13 #include <stdint.h>
14 #include <pthread.h>
15 
16 /* Default shmlog size if not set by user. */
17 extern const int default_shmlog_size;
18 
19 /*
20  * Header of the shmlog file. Used by i3/src/log.c and i3/i3-dump-log/main.c.
21  *
22  */
23 typedef struct i3_shmlog_header {
24  /* Byte offset where the next line will be written to. */
26 
27  /* Byte offset where the last wrap occured. */
28  uint32_t offset_last_wrap;
29 
30  /* The size of the logfile in bytes. Since the size is limited to 25 MiB
31  * an uint32_t is sufficient. */
32  uint32_t size;
33 
34  /* wrap counter. We need it to reliably signal to clients that we just
35  * wrapped (clients cannot use offset_last_wrap because that might
36  * coincidentally be exactly the same as previously). Overflows can happen
37  * and don’t matter — clients use an equality check (==). */
38  uint32_t wrap_count;
39 
40  /* pthread condvar which will be broadcasted whenever there is a new
41  * message in the log. i3-dump-log uses this to implement -f (follow, like
42  * tail -f) in an efficient way. */
43  pthread_cond_t condvar;
uint32_t wrap_count
Definition: shmlog.h:38
uint32_t size
Definition: shmlog.h:32
uint32_t offset_next_write
Definition: shmlog.h:25
uint32_t offset_last_wrap
Definition: shmlog.h:28
pthread_cond_t condvar
Definition: shmlog.h:43
const int default_shmlog_size
Definition: main.c:77
struct i3_shmlog_header i3_shmlog_header