Input and Output [POSIX Section 6]

int dup( int fd ); 
int dup2( int fd, int fd2 ); 
int close(int fd); 
ssize_t	read(int fd, void *buf, size_t nbyte); 
ssize_t	write(int fd, const void *buf, size_t nbyte); 
int fcntl( int fd, int cmd, ... ); 
off_t lseek(int fd, off_t offset, int whence); 
int fsync( int fd );
int fdatasync( int fd );

int pipe( int fildes[2] ); 
int aio_read( struct aiocb *aiocbp );				// TBA 
int aio_write( struct aiocb *aiocbp );				// TBA 
int lio_listio( int mode, struct aiocb *const list[],
                int nent, struct sigevent *sig);		// TBA 
int aio_error( struct aiocb *aiocbp );				// TBA 
int aio_return( struct aiocb *aiocbp );				// TBA 
int aio_cancel( int fd, struct aiocb *aiocbp );			// TBA 
int aio_suspend( const struct aiocb *const list[],
                 int nent, const struct timespec *timeout );	// TBA 
int aio_fsync( int op, struct aiocb *aiocbp );
// TBA