diff --git a/dcapi/include/dc_client.h b/dcapi/include/dc_client.h
index c622448c37..08502615b2 100644
--- a/dcapi/include/dc_client.h
+++ b/dcapi/include/dc_client.h
@@ -1,7 +1,7 @@
 /* API for Master-worker applications on Distributed Computing Platforms
    API for the Client program
-   v0.2 Norbert Podhorszki
-   MTA SZTAKI, 2004
+   v0.4 Norbert Podhorszki, and Gabor Vida
+   MTA SZTAKI, 2006
 */
 #ifndef __DCCLIENT_H_
 #define __DCCLIENT_H_
@@ -10,6 +10,49 @@
 extern "C" {
 #endif
 
+/* For return value */
+#define DC_OK	 0
+#define DC_ERROR 1
+
+/* For the DC_ResolveFileName function */
+#define INPUT_FILE	0
+#define OUTPUT_FILE	1
+#define CKPT_FILE	2
+#define TEMP_FILE	3
+
+
+/** Inicialize the client API.
+ *  Some kind of init is usually required in most of the GRIDs!
+ *
+ *  Return: DC_OK
+ */
+int DC_Init(void);
+
+
+/** File name resolution
+ * The real file name (and path) of an input/output file may be different from what
+ * the application expects. It should ask the API about the actual path.
+ * It may want to open input file 'inp.txt' in the actual directory but
+ * the actual file may be e.g. '../project/szdg_lpds_sztaki_hu_szdg/inp.txt09247814354'
+ *
+ * The first "type" parameter decides what is the type of the requested file:
+ * --> input: 0, output: 1, ckpt: 2, tmp: 3
+ *
+ * Usage:
+ *   char fname[256];
+ *   dc_ResolveFileName(INPUT_FILE, "inp.txt", fname, 256);
+ *   f = fopen(fname);
+ *
+ * Return: DC_OK always
+ */
+int DC_ResolveFileName(
+    int type,
+    conts char *requestedFileName,
+    char       *actualFileName,
+    int maxlength
+);
+
+
 /** Send a (partial) result back to the master.
  *  Parameters:
  *      files    list of created output files to be sent back
@@ -17,10 +60,27 @@ extern "C" {
  *
  *  Return: DC_OK
  */
-int DC_SendResult(char **files,  // output files
-		  int nfiles     // number of output files
+int DC_SendResult(char **files,
+		  int nfiles
 		  );
 
+
+/** Is it time to make a checkpoint?
+ *  Return: 0 No, 1 Yes
+ *
+ *  Comment: fast function, it can be called very regularly.
+ *           BOINC provides such functionality, for ClusterGrid,
+ *           the api answers Yes every 5 minutes.
+ */
+int DC_TimeToCheckpoint(void);
+
+
+/** User/level checkpoint made.
+ *  Return: DC_OK
+ */
+int DC_CheckpointMade(void);
+
+
 /** Check if work can be continued. (Ask master)
  *  This involves network communication and may block long.
  *  Parameters:
@@ -33,6 +93,15 @@ int DC_SendResult(char **files,  // output files
 int DC_ContinueWork(void);
 
 
+/** Informs about the fraction already done!
+ *  Parameter:
+ *       fraction - a double value of   work already done / total work
+ *
+ *  Return: DC_OK
+ */
+int DC_FractionDone(double fraction);
+
+
 /** Finish computation.
  *  Tell DC to finish this work unit and start a new one.
  *  It should be called as the last function and then exit.