-void MD5_Init(MD5_CTX *c);
-void MD5_Update(MD5_CTX *c, const unsigned char *data, unsigned long len);
-void MD5_Final(unsigned char *md, MD5_CTX *c);
-unsigned char *MD5(const unsigned char *d, unsigned long n, unsigned char *md);
+int MD5_Init(MD5_CTX *c);
+int MD5_Update(MD5_CTX *c, const void *data, size_t len);
+int MD5_Final(unsigned char *md, MD5_CTX *c);
+unsigned char *MD5(const unsigned char *d, size_t n, unsigned char *md);