#define _IOFBF 0		/* Fully buffered.  */
#define _IOLBF 1		/* Line buffered.  */
#define _IONBF 2		/* No buffering.  */

void setbuf (FILE *__restrict __stream, char *__restrict __buf);
int setvbuf (FILE *__restrict __stream, char *__restrict __buf, int __modes, size_t __n);

FILE *fdopen (int __fd, const char *__modes);
int fileno (FILE *__stream);

FILE *fmemopen (void *__s, size_t __len, const char *__modes);