Add some clarifying defines.
In order to be explicit in the Backtrace::Create() calls, adding a couple
of defines and some comments to describe what they mean.
Change-Id: I6ad08c529791821496a95fa33cea1c95b0a7eada
diff --git a/include/backtrace/backtrace.h b/include/backtrace/backtrace.h
index b35a6d5..a833982 100644
--- a/include/backtrace/backtrace.h
+++ b/include/backtrace/backtrace.h
@@ -23,6 +23,14 @@
__BEGIN_DECLS
+// When the pid to be traced is set to this value, then trace the current
+// process. If the tid value is not BACKTRACE_NO_TID, then the specified
+// thread from the current process will be traced.
+#define BACKTRACE_CURRENT_PROCESS -1
+// When the tid to be traced is set to this value, then trace the specified
+// pid.
+#define BACKTRACE_NO_TID -1
+
#define MAX_BACKTRACE_FRAMES 64
typedef struct backtrace_map_info {