+ The C 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.
+
+ Things used to say "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." at this point.
+ However, then somebody birthed C++11 into the world, which copied POSIX's
+ errno values into C++. Yes, even EINTR. Therefore, this library defines
+ them. That said, thats nothing stopping you from using your own error
+ reporting facility for things outside the C library.
+
+ Sometimes the standard says to set errno to indicate an error, but does not
+ prescribe a value. We will use a value from the following list. If POSIX
+ defines a value, we use that; otherwise, we use as seems suitable.
+
+ If porting to a system which uses an errno-like reporting system (e.g. a
+ UNIX), you'll probably want to define them to match what the OS uses
+*/
+/* C errno values */
+#define _PDCLIB_ERANGE 1
+#define _PDCLIB_EDOM 2
+#define _PDCLIB_EILSEQ 3
+
+/* C++11/POSIX errno values */
+#define _PDCLIB_E2BIG 4
+#define _PDCLIB_ECONNRESET 5
+#define _PDCLIB_EISCONN 6
+#define _PDCLIB_ENOENT 7
+#define _PDCLIB_ENOTRECOVERABLE 8
+#define _PDCLIB_EROFS 9
+#define _PDCLIB_EACCES 10
+#define _PDCLIB_EDEADLK 11
+#define _PDCLIB_EISDIR 12
+#define _PDCLIB_ENOEXEC 13
+#define _PDCLIB_ENOTSOCK 14
+#define _PDCLIB_ESPIPE 15
+#define _PDCLIB_EADDRINUSE 16
+#define _PDCLIB_EDESTADDRREQ 17
+#define _PDCLIB_ELOOP 18
+#define _PDCLIB_ENOLCK 19
+#define _PDCLIB_ENOTSUPP 20
+#define _PDCLIB_ESRCH 21
+#define _PDCLIB_EADDRNOTAVAIL 22
+#define _PDCLIB_EMFILE 23
+#define _PDCLIB_ENOLINK 24
+#define _PDCLIB_ENOTTY 25
+#define _PDCLIB_ETIME 26
+#define _PDCLIB_EAFNOSUPPORT 27
+#define _PDCLIB_EEXIST 28
+#define _PDCLIB_EMLINK 29
+#define _PDCLIB_ENOMEM 30
+#define _PDCLIB_ENXIO 31
+#define _PDCLIB_ETIMEDOUT 32
+#define _PDCLIB_EAGAIN 33
+#define _PDCLIB_EFAULT 34
+#define _PDCLIB_EMSGSIZE 35
+#define _PDCLIB_ENOMSG 36
+#define _PDCLIB_EOPNOTSUPP 37
+#define _PDCLIB_ETXTBSY 38
+#define _PDCLIB_EALREADY 39
+#define _PDCLIB_EFBIG 40
+#define _PDCLIB_ENAMETOOLONG 41
+#define _PDCLIB_ENOPROTOOPT 42
+#define _PDCLIB_EOVERFLOW 43
+#define _PDCLIB_EWOULDBLOCK _PDCLIB_EAGAIN
+#define _PDCLIB_EBADF 44
+#define _PDCLIB_EHOSTUNREACH 45
+#define _PDCLIB_ENETDOWN 46
+#define _PDCLIB_ENOSPC 47
+#define _PDCLIB_EOWNERDEAD 48
+#define _PDCLIB_EXDEV 49
+#define _PDCLIB_EBADMSG 50
+#define _PDCLIB_EIDRM 51
+#define _PDCLIB_ENETRESET 52
+#define _PDCLIB_ENOSR 53
+#define _PDCLIB_EPERM 54
+#define _PDCLIB_EBUSY 55
+#define _PDCLIB_ENETUNREACH 56
+#define _PDCLIB_ENOSTR 57
+#define _PDCLIB_EPIPE 58
+#define _PDCLIB_ECANCELED 59
+#define _PDCLIB_EINPROGRESS 60
+#define _PDCLIB_ENFILE 61
+#define _PDCLIB_ENOSYS 62
+#define _PDCLIB_EPROTO 63
+#define _PDCLIB_ECHILD 64
+#define _PDCLIB_EINTR 65
+#define _PDCLIB_ENOBUFS 66
+#define _PDCLIB_ENOTCONN 67
+#define _PDCLIB_EPROTONOSUPPORT 68
+#define _PDCLIB_ECONNABORTED 69
+#define _PDCLIB_EINVAL 70
+#define _PDCLIB_ENODATA 71
+#define _PDCLIB_ENOTDIR 72
+#define _PDCLIB_EPROTOTYPE 73
+
+#endif