diff --git a/tracker.c b/tracker.c
index 2d35429a..f460a160 100644
--- a/tracker.c
+++ b/tracker.c
@@ -1,5 +1,40 @@
 #include <glib.h>
 #include "tracker.h"
+#include "stackstash.h"
+
+typedef struct new_process_t new_process_t;
+typedef struct new_map_t new_map_t;
+typedef struct sample_t sample_t;
+typedef union  time_line_entry_t time_line_entry_t;
+
+struct new_process_t
+{
+    pid_t	pid;
+    char	command_line[64];
+};
+
+struct new_map_t
+{
+    char	file_name[PATH_MAX];
+    pid_t	pid;
+    uint64_t	start;
+    uint64_t	end;
+    uint64_t	offset;
+    uint64_t	inode;
+};
+
+struct sample_t
+{
+    pid_t		 pid;
+    StackNode		*trace;
+};
+
+union time_line_entry_t
+{
+    new_process_t	new_process;
+    new_map_t		new_map;
+    sample_t		sample;
+};
 
 struct tracker_t
 {
@@ -38,5 +73,5 @@ tracker_add_sample  (tracker_t *tracker,
 Profile *
 tracker_create_profile (tracker_t *tracker)
 {
-    
+
 }