include/babeltrace/context.h

   1 #ifndef _BABELTRACE_CONTEXT_H
   2 #define _BABELTRACE_CONTEXT_H
   3
   4 /*
   5  * BabelTrace
   6  *
   7  * context header
   8  *
   9  * Copyright 2012 EfficiOS Inc. and Linux Foundation
  10  *
  11  * Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  12  *         Julien Desfossez <julien.desfossez@efficios.com>
  13  *
  14  * Permission is hereby granted, free of charge, to any person obtaining
  15  * a copy of this software and associated documentation files (the
  16  * "Software"), to deal in the Software without restriction, including
  17  * without limitation the rights to use, copy, modify, merge, publish,
  18  * distribute, sublicense, and/or sell copies of the Software, and to
  19  * permit persons to whom the Software is furnished to do so, subject to
  20  * the following conditions:
  21  *
  22  * The above copyright notice and this permission notice shall be
  23  * included in all copies or substantial portions of the Software.
  24  */
  25
  26 /* struct bt_context is opaque to the user */
  27 struct bt_context;
  28
  29 /*
  30  * bt_context_create : create a Babeltrace context
  31  *
  32  * Allocate a new context. The creation of the context sets the refcount
  33  * to 1.
  34  *
  35  * Returns an allocated context on success and NULL on error
  36  */
  37 struct bt_context *bt_context_create(void);
  38
  39 /*
  40  * bt_context_add_trace : Add a trace by path to the context
  41  *
  42  * Open a trace
  43  *
  44  * Return: the trace handle id (>= 0) on success, a negative
  45  * value on error.
  46  */
  47 int bt_context_add_trace(struct bt_context *ctx, const char *path,
  48                 const char *format);
  49
  50 /*
  51  * bt_context_remove_trace: Remove a trace from the context.
  52  *
  53  * Effectively closing the trace.
  54  */
  55 void bt_context_remove_trace(struct bt_context *ctx, int trace_id);
  56
  57 /*
  58  * bt_context_get and bt_context_put : increments and decrement the
  59  * refcount of the context
  60  *
  61  * These functions ensures that the context won't be destroyed when it
  62  * is in use. The same number of get and put (plus one extra put to
  63  * release the initial reference done at creation) has to be done to
  64  * destroy a context.
  65  *
  66  * When the context refcount is decremented to 0 by a bt_context_put,
  67  * the context is freed.
  68  */
  69 void bt_context_get(struct bt_context *ctx);
  70 void bt_context_put(struct bt_context *ctx);
  71
  72 #endif /* _BABELTRACE_CONTEXT_H */