// opening and closing streams
// opens a stream
-void *dpvsimpledecode_open(char *filename, char **errorstring)
+void *dpvsimpledecode_open(char *filename, const char **errorstring)
{
dpvsimpledecodestream_t *s;
char t[8], *wavename;
// number to DPVSIMPLEDECODEERROR_NONE
// if the supplied string pointer variable is not NULL, it will be set to the
// error message
-int dpvsimpledecode_error(void *stream, char **errorstring)
+int dpvsimpledecode_error(void *stream, const char **errorstring)
{
dpvsimpledecodestream_t *s = (dpvsimpledecodestream_t *)stream;
int e;