-/* A system call that writes n characters to a file identified by given file
- descriptor. Return the number of characters actually written, or zero if
- an error occured.
+/* A system call that writes a stream's buffer.
+ Returns 0 on success, EOF on write error.
+ Sets stream error flags and errno appropriately on error.
+*/
+int _PDCLIB_flushbuffer( struct _PDCLIB_file_t * stream );
+
+/* A system call that fills a stream's buffer.
+ Returns 0 on success, EOF on read error / EOF.
+ Sets stream EOF / error flags and errno appropriately on error.