+/* -------------------------------------------------------------------------- */
+/* Declaration of helper functions (implemented in functions/_PDCLIB). */
+/* -------------------------------------------------------------------------- */
+
+/* This is the main function called by atoi(), atol() and atoll(). */
+_PDCLIB_intmax_t _PDCLIB_atomax( const char * s );
+
+/* Two helper functions used by strtol(), strtoul() and long long variants. */
+const char * _PDCLIB_strtox_prelim( const char * p, char * sign, int * base );
+_PDCLIB_uintmax_t _PDCLIB_strtox_main( const char ** p, unsigned int base, _PDCLIB_uintmax_t error, _PDCLIB_uintmax_t limval, int limdigit, char * sign );
+
+/* Digits arrays used by various integer conversion functions */
+extern char _PDCLIB_digits[];
+extern char _PDCLIB_Xdigits[];
+
+/* -------------------------------------------------------------------------- */
+/* 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>.
+*/
+extern int _PDCLIB_errno;
+
+/* A mechanism for delayed evaluation. (Not sure if this is really necessary, so
+ no detailed documentation on the "why".)
+*/
+int * _PDCLIB_errno_func( void ) _PDCLIB_nothrow;
+
+/* -------------------------------------------------------------------------- */
+/* <ctype.h> lookup tables */
+/* -------------------------------------------------------------------------- */
+
+#define _PDCLIB_CTYPE_ALPHA 1
+#define _PDCLIB_CTYPE_BLANK 2
+#define _PDCLIB_CTYPE_CNTRL 4
+#define _PDCLIB_CTYPE_GRAPH 8
+#define _PDCLIB_CTYPE_PUNCT 16
+#define _PDCLIB_CTYPE_SPACE 32
+#define _PDCLIB_CTYPE_LOWER 64
+#define _PDCLIB_CTYPE_UPPER 128
+#define _PDCLIB_CTYPE_DIGIT 256
+#define _PDCLIB_CTYPE_XDIGT 512
+
+struct _PDCLIB_ctype_t