+#define RAND_MAX 0x7fffffff
+
+/* initialize random seed */
+void srand(unsigned long seed);
+
+/* return a random number between 0 and RAND_MAX */
+long rand(void);
+
+/* reentrant version of rand() */
+long rand_r(unsigned long *ctx);
+
+
+/* returns the CRC16 checksum of the data buffer, takes as
+ * last argument an old value of crc16 checksum */
+uint16_t crc16(uint8_t *, uint32_t, uint16_t);
+
+
+/* convert a ASCII string to float */
+float atof (char *);
+
+/* convert a ASCII string to integer */
+int atoi (char *);
+
+/* convert a ASCII string to long */
+long atol (char *);