+/* The values of SEEK_SET, SEEK_CUR and SEEK_END, used by fseek().
+ Since at least one platform (POSIX) uses the same symbols for its own "seek"
+ function, we use whatever the host defines (if it does define them).
+*/
+#define _PDCLIB_SEEK_SET 0
+#define _PDCLIB_SEEK_CUR 1
+#define _PDCLIB_SEEK_END 2
+
+/* The number of characters that can be buffered with ungetc(). The standard
+ guarantees only one (1); anything larger would make applications relying on
+ this capability dependent on implementation-defined behaviour (not good).
+*/
+#define _PDCLIB_UNGETCBUFSIZE 1
+
+/* errno -------------------------------------------------------------------- */
+
+/* These are the values that _PDCLIB_errno can be set to by the library.
+
+ By keeping PDCLib's errno in the _PDCLIB_* namespace, the library is capable
+ to "translate" between errno values used by the hosting operating system and
+ those used and passed out by the library.
+
+ Example: In the example platform, the remove() function uses the unlink()
+ system call as backend. Linux sets its errno to EISDIR if you try to unlink()
+ a directory, but POSIX demands EPERM. Within the remove() function, you can
+ catch the 'errno == EISDIR', and set '_PDCLIB_errno = _PDCLIB_EPERM'. Anyone
+ using PDCLib's <errno.h> will "see" EPERM instead of EISDIR (the _PDCLIB_*
+ prefix removed by <errno.h> mechanics).
+
+ If you do not want that kind of translation, you might want to "match" the
+ values used by PDCLib with those used by the host OS, as to avoid confusion.
+
+ The standard only defines three distinct errno values: ERANGE, EDOM, and
+ EILSEQ. The standard leaves it up to "the implementation" whether there are
+ any more beyond those three. There is some controversy as to whether errno is
+ such a good idea at all, so you might want to come up with a different error
+ reporting facility for your platform. Since errno values beyond the three
+ defined by the standard are not portable anyway (unless you look at POSIX),
+ having your own error reporting facility would not hurt anybody either.