static int ism_write(istream_t * istream, const void * data, int n) { return ism_read_or_write(istream, (void *)data, n, ISTREAM_OPEN_WRITE); }
static int ism_write(istream_t * istream, const void * data, int n) { return ism_read_or_write(istream, n); }
static int ism_read(istream_t * istream, void * data, int n) { return ism_read_or_write(istream, data, n, ISTREAM_OPEN_READ); }