Merge branch 'release-4.16.1'

[i3/i3] / include / shmlog.h

diff --git a/include/shmlog.h b/include/shmlog.h
index c513babf698e3e931ecabb011e024dde2a95cba3..dc8081f1329c8e6a24d2646c19428127efe594ce 100644 (file)
--- a/include/shmlog.h
+++ b/include/shmlog.h
@@ -2,21 +2,49 @@
  * vim:ts=4:sw=4:expandtab
  *
  * i3 - an improved dynamic tiling window manager
- * © 2009-2012 Michael Stapelberg and contributors (see also: LICENSE)
+ * © 2009 Michael Stapelberg and contributors (see also: LICENSE)
  *
  * The format of the shmlog data structure which i3 development versions use by
  * default (ringbuffer for storing the debug log).
  *
  */
-#ifndef _I3_SHMLOG_H
-#define _I3_SHMLOG_H
+#pragma once
+
+#include <config.h>
 
 #include <stdint.h>
+#if !defined(__OpenBSD__)
+#include <pthread.h>
+#endif
+
+/* Default shmlog size if not set by user. */
+extern const int default_shmlog_size;
 
+/**
+ * Header of the shmlog file. Used by i3/src/log.c and i3/i3-dump-log/main.c.
+ *
+ */
 typedef struct i3_shmlog_header {
+    /* Byte offset where the next line will be written to. */
     uint32_t offset_next_write;
+
+    /* Byte offset where the last wrap occurred. */
     uint32_t offset_last_wrap;
+
+    /* The size of the logfile in bytes. Since the size is limited to 25 MiB
+     * an uint32_t is sufficient. */
     uint32_t size;
-} i3_shmlog_header;
 
+    /* wrap counter. We need it to reliably signal to clients that we just
+     * wrapped (clients cannot use offset_last_wrap because that might
+     * coincidentally be exactly the same as previously). Overflows can happen
+     * and don’t matter — clients use an equality check (==). */
+    uint32_t wrap_count;
+
+#if !defined(__OpenBSD__)
+    /* pthread condvar which will be broadcasted whenever there is a new
+     * message in the log. i3-dump-log uses this to implement -f (follow, like
+     * tail -f) in an efficient way. */
+    pthread_cond_t condvar;
 #endif
+} i3_shmlog_header;