*/
#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.
+*/
+#define _PDCLIB_ERANGE 1
+#define _PDCLIB_EDOM 2
+#define _PDCLIB_EILSEQ 3
+
+/* The following is not strictly "configuration", but there is no better place
+ to explain it than here.
+
+ PDCLib strives to be as generic as possible, so by default it does NOT define
+ any values beyond the three standard ones above, even where it would have
+ been prudent and convenient to do so. Any errno "caught" from the host OS,
+ and some internal error conditions as well, are all lumped together into the
+ value of '_PDCLIB_ERROR'.
+
+ '_PDCLIB_ERROR' is STRICLY meant as a PLACEHOLDER only.
+
+ You should NEVER ship an adaption of PDCLib still using that particular
+ value. You should NEVER write code that *tests* for that value. Indeed it is
+ not even conforming, since errno values should be defined as beginning with
+ an uppercase 'E', and there is no mechanics in <errno.h> to unmask that
+ particular value (for exactly that reason).
+
+ There also is no error message available for this value through either the
+ strerror() or perror() functions. It is being reported as "unknown" error.
+
+ The idea is that you scan the source of PDCLib for occurrences of this macro
+ and replace _PDCLIB_ERROR with whatever additional errno value you came up
+ with for your platform.
+
+ If you cannot find it within you to do that, tell your clients to check for
+ an errno value larger than zero. That, at least, would be standard compliant
+ (and fully portable).
+*/
+#define _PDCLIB_ERROR 4
+
+/* The maximum value that errno can be set to. This is used to set the size */
+/* of the array in struct lconv (<locale.h>) holding error messages for the */
+/* strerror() and perror() functions. (If you change this value because you */
+/* are using additional errno values, you *HAVE* to provide appropriate error */
+/* messages for *ALL* locales.) */
+/* Default is 4 (0, ERANGE, EDOM, EILSEQ). */
+#define _PDCLIB_ERRNO_MAX 4
+
#endif
projects / pdclib / blobdiff