+/* Digits arrays used by various integer conversion functions */
+extern char _PDCLIB_digits[];
+extern char _PDCLIB_Xdigits[];
+
+/* The worker for all printf() type of functions. The pointer spec should point
+ to the introducing '%' of a conversion specifier. The status structure is to
+ be that of the current printf() function, of which the members n, s, stream
+ and arg will be preserved; i will be updated; and all others will be trashed
+ by the function.
+ Returns a pointer to the first character not parsed as conversion specifier.
+*/
+const char * _PDCLIB_print( const char * spec, struct _PDCLIB_status_t * status );
+
+/* The worker for all scanf() type of functions. The pointer spec should point
+ to the introducing '%' of a conversion specifier. The status structure is to
+ be that of the current scanf() function, of which the member stream will be
+ preserved; n, i, and s will be updated; and all others will be trashed by
+ the function.
+ Returns a pointer to the first character not parsed as conversion specifier,
+ or NULL in case of error.
+ FIXME: Should distinguish between matching and input error
+*/
+const char * _PDCLIB_scan( const char * spec, struct _PDCLIB_status_t * status );
+
+/* Parsing any fopen() style filemode string into a number of flags. */
+unsigned int _PDCLIB_filemode( const char * mode );
+
+/* Sanity checking and preparing of read buffer, should be called first thing
+ by any stdio read-data function.
+ Returns 0 on success, EOF on error.
+ On error, EOF / error flags and errno are set appropriately.
+*/
+int _PDCLIB_prepread( struct _PDCLIB_file_t * stream );
+
+/* Sanity checking, should be called first thing by any stdio write-data
+ function.
+ Returns 0 on success, EOF on error.
+ On error, error flags and errno are set appropriately.
+*/
+int _PDCLIB_prepwrite( struct _PDCLIB_file_t * stream );
+
+/* Closing all streams on program exit */
+void _PDCLIB_closeall( void );
+
+/* -------------------------------------------------------------------------- */
+/* errno */
+/* -------------------------------------------------------------------------- */
+
+/* If PDCLib would call its error number "errno" directly, there would be no way
+ to catch its value from underlying system calls that also use it (i.e., POSIX
+ operating systems). That is why we use an internal name, providing a means to
+ access it through <errno.h>.