Simplify errno2.h slightly

There is no need for it to worry about ensuring that standard errno.h values
like EINTR are defined.

There is no point in it defining dummy constants like EINVALIDPROCTABLE which
do not exist in errno.h at all. They would only be given the corresponding
WSAExxx values anyway, so the win32sck.c function might just as well return
them directly.

Other constants like ESOCKTNOSUPPORT which do not exist in errno.h on Windows
but presumably exist elsewhere since POSIX tries to exports them are still
worth defining (where possible -- it isn't possible for EHOSTDOWN since there
is no corresponding WSAEHOSTDOWN); add comments for these for clarity.

Also comment which errno.h constants are new in VC10, and mention three of
the four that win32/include/sys/socket.h used to redefine because they are
used in the perl core (ENOTSOCK, EAFNOSUPPORT and ECONNABORTED) -- the other
one (ECONNRESET) does not appear to be used in the perl core as far as I can
tell.

2 files changed, 92 insertions, 99 deletions

diff --git a/win32/include/sys/errno2.h b/win32/include/sys/errno2.h
index 084e9e4f22..b4749a3188 100644
--- a/win32/include/sys/errno2.h
+++ b/win32/include/sys/errno2.h
@@ -4,166 +4,156 @@
 #define _WINSOCKAPI_	/* Don't drag in everything */
 #include <winsock.h>
 
-/* Ensure all the Exxx constants required by get_last_socket_error() in
- * win32/win32sck.c are defined. Many are defined in <errno.h> already (more in
- * VC++ 2010 and above) so, for the sake of compatibility with third-party code
- * linked into XS modules, we must be careful not to redefine them; for the
- * remainder we define our own values, namely the corresponding WSAExxx values.
+/* Ensure all the Exxx constants required by convert_wsa_error_to_errno() in
+ * win32/win32sck.c are defined. Many are defined in <errno.h> already (more so
+ * in VC++ 2010 and above, which have an extra "POSIX supplement") so, for the
+ * sake of compatibility with third-party code linked into XS modules, we must
+ * be careful not to redefine them; for the remainder we define our own values,
+ * namely the corresponding WSAExxx values.
+ *
  * These definitions are also used as a supplement to the use of <errno.h> in
  * the Errno and POSIX modules, both of which may be used to test the value of
- * $!, which may have these values assigned to it (via win32/win32sck.c). It
- * also provides numerous otherwise missing values in the (hard-coded) list of
- * Exxx constants exported by POSIX.
+ * $!, which may have these values assigned to it (via code in win32/win32sck.c
+ * and the $! case in Perl_magic_set()). It also provides numerous otherwise
+ * missing values in the (hard-coded) list of Exxx constants exported by POSIX.
+ * Finally, three of the non-standard errno.h values (actually all now in the
+ * POSIX supplement in VC10+) are used in the perl core.
+ *
+ * This list is in the same order as that in convert_wsa_error_to_errno(). A
+ * handful of WSAExxx constants used by that function have no corresponding Exxx
+ * constant in any errno.h so there is no point in making up values for them;
+ * they are just returned unchanged by that function so we do not need to worry
+ * about them here.
  */
-#ifndef EINTR
-#  define EINTR			WSAEINTR
-#endif
-#ifndef EBADF
-#  define EBADF			WSAEBADF
-#endif
-#ifndef EACCES
-#  define EACCES		WSAEACCES
-#endif
-#ifndef EFAULT
-#  define EFAULT		WSAEFAULT
-#endif
-#ifndef EINVAL
-#  define EINVAL		WSAEINVAL
-#endif
-#ifndef EMFILE
-#  define EMFILE		WSAEMFILE
-#endif
-#ifndef EWOULDBLOCK
+
+/* EINTR is a standard errno.h value */
+/* EBADF is a standard errno.h value */
+/* EACCES is a standard errno.h value */
+/* EFAULT is a standard errno.h value */
+/* EINVAL is a standard errno.h value */
+/* EMFILE is a standard errno.h value */
+
+#ifndef EWOULDBLOCK		/* New in VC10 */
 #  define EWOULDBLOCK		WSAEWOULDBLOCK
 #endif
-#ifndef EINPROGRESS
+#ifndef EINPROGRESS		/* New in VC10 */
 #  define EINPROGRESS		WSAEINPROGRESS
 #endif
-#ifndef EALREADY
+#ifndef EALREADY		/* New in VC10 */
 #  define EALREADY		WSAEALREADY
 #endif
-#ifndef ENOTSOCK
+#ifndef ENOTSOCK		/* New in VC10 and needed in doio.c */
 #  define ENOTSOCK		WSAENOTSOCK
 #endif
-#ifndef EDESTADDRREQ
+#ifndef EDESTADDRREQ		/* New in VC10 */
 #  define EDESTADDRREQ		WSAEDESTADDRREQ
 #endif
-#ifndef EMSGSIZE
+#ifndef EMSGSIZE		/* New in VC10 */
 #  define EMSGSIZE		WSAEMSGSIZE
 #endif
-#ifndef EPROTOTYPE
+#ifndef EPROTOTYPE		/* New in VC10 */
 #  define EPROTOTYPE		WSAEPROTOTYPE
 #endif
-#ifndef ENOPROTOOPT
+#ifndef ENOPROTOOPT		/* New in VC10 */
 #  define ENOPROTOOPT		WSAENOPROTOOPT
 #endif
-#ifndef EPROTONOSUPPORT
+#ifndef EPROTONOSUPPORT		/* New in VC10 */
 #  define EPROTONOSUPPORT	WSAEPROTONOSUPPORT
 #endif
-#ifndef ESOCKTNOSUPPORT
+#ifndef ESOCKTNOSUPPORT		/* Not in errno.h but wanted by POSIX.pm */
 #  define ESOCKTNOSUPPORT	WSAESOCKTNOSUPPORT
 #endif
-#ifndef EOPNOTSUPP
+#ifndef EOPNOTSUPP		/* New in VC10 */
 #  define EOPNOTSUPP		WSAEOPNOTSUPP
 #endif
-#ifndef EPFNOSUPPORT
+#ifndef EPFNOSUPPORT		/* Not in errno.h but wanted by POSIX.pm */
 #  define EPFNOSUPPORT		WSAEPFNOSUPPORT
 #endif
-#ifndef EAFNOSUPPORT
+#ifndef EAFNOSUPPORT		/* New in VC10 and needed in util.c */
 #  define EAFNOSUPPORT		WSAEAFNOSUPPORT
 #endif
-#ifndef EADDRINUSE
+#ifndef EADDRINUSE		/* New in VC10 */
 #  define EADDRINUSE		WSAEADDRINUSE
 #endif
-#ifndef EADDRNOTAVAIL
+#ifndef EADDRNOTAVAIL		/* New in VC10 */
 #  define EADDRNOTAVAIL		WSAEADDRNOTAVAIL
 #endif
-#ifndef ENETDOWN
+#ifndef ENETDOWN		/* New in VC10 */
 #  define ENETDOWN		WSAENETDOWN
 #endif
-#ifndef ENETUNREACH
+#ifndef ENETUNREACH		/* New in VC10 */
 #  define ENETUNREACH		WSAENETUNREACH
 #endif
-#ifndef ENETRESET
+#ifndef ENETRESET		/* New in VC10 */
 #  define ENETRESET		WSAENETRESET
 #endif
-#ifndef ECONNABORTED
+#ifndef ECONNABORTED		/* New in VC10 and needed in util.c */
 #  define ECONNABORTED		WSAECONNABORTED
 #endif
-#ifndef ECONNRESET
+#ifndef ECONNRESET		/* New in VC10 */
 #  define ECONNRESET		WSAECONNRESET
 #endif
-#ifndef ENOBUFS
+#ifndef ENOBUFS			/* New in VC10 */
 #  define ENOBUFS		WSAENOBUFS
 #endif
-#ifndef EISCONN
+#ifndef EISCONN			/* New in VC10 */
 #  define EISCONN		WSAEISCONN
 #endif
-#ifndef ENOTCONN
+#ifndef ENOTCONN		/* New in VC10 */
 #  define ENOTCONN		WSAENOTCONN
 #endif
-#ifndef ESHUTDOWN
+#ifndef ESHUTDOWN		/* Not in errno.h but wanted by POSIX.pm */
 #  define ESHUTDOWN		WSAESHUTDOWN
 #endif
-#ifndef ETOOMANYREFS
+#ifndef ETOOMANYREFS		/* Not in errno.h but wanted by POSIX.pm */
 #  define ETOOMANYREFS		WSAETOOMANYREFS
 #endif
-#ifndef ETIMEDOUT
+#ifndef ETIMEDOUT		/* New in VC10 */
 #  define ETIMEDOUT		WSAETIMEDOUT
 #endif
-#ifndef ECONNREFUSED
+#ifndef ECONNREFUSED		/* New in VC10 */
 #  define ECONNREFUSED		WSAECONNREFUSED
 #endif
-#ifndef ELOOP
+#ifndef ELOOP			/* New in VC10 */
 #  define ELOOP			WSAELOOP
 #endif
-#ifndef ENAMETOOLONG
-#  define ENAMETOOLONG		WSAENAMETOOLONG
-#endif
-#ifndef EHOSTDOWN
-#  define EHOSTDOWN		WSAEHOSTDOWN
-#endif
-#ifndef EHOSTUNREACH
+
+/* ENAMETOOLONG is a standard errno.h value */
+
+/* EHOSTDOWN is not an errno.h value at all (on Windows, anyway) */
+
+#ifndef EHOSTUNREACH		/* New in VC10 */
 #  define EHOSTUNREACH		WSAEHOSTUNREACH
 #endif
-#ifndef ENOTEMPTY
-#  define ENOTEMPTY		WSAENOTEMPTY
-#endif
-#ifndef EPROCLIM
+
+/* ENOTEMPTY is a standard errno.h value */
+
+#ifndef EPROCLIM		/* Not in errno.h but wanted by POSIX.pm */
 #  define EPROCLIM		WSAEPROCLIM
 #endif
-#ifndef EUSERS
+#ifndef EUSERS			/* Not in errno.h but wanted by POSIX.pm */
 #  define EUSERS		WSAEUSERS
 #endif
-#ifndef EDQUOT
+#ifndef EDQUOT			/* Not in errno.h but wanted by POSIX.pm */
 #  define EDQUOT		WSAEDQUOT
 #endif
-#ifndef ESTALE
+#ifndef ESTALE			/* Not in errno.h but wanted by POSIX.pm */
 #  define ESTALE		WSAESTALE
 #endif
-#ifndef EREMOTE
+#ifndef EREMOTE			/* Not in errno.h but wanted by POSIX.pm */
 #  define EREMOTE		WSAEREMOTE
 #endif
-#ifndef EDISCON
-#  define EDISCON		WSAEDISCON
-#endif
-#ifndef ENOMORE
-#  define ENOMORE		WSAENOMORE
-#endif
-#ifndef ECANCELED
+
+/* EDISCON is not an errno.h value at all */
+/* ENOMORE is not an errno.h value at all */
+
+#ifndef ECANCELED		/* New in VC10 */
 #  define ECANCELED		WSAECANCELLED
 #endif
-#ifndef EINVALIDPROCTABLE
-#  define EINVALIDPROCTABLE	WSAEINVALIDPROCTABLE
-#endif
-#ifndef EINVALIDPROVIDER
-#  define EINVALIDPROVIDER	WSAEINVALIDPROVIDER
-#endif
-#ifndef EPROVIDERFAILEDINIT
-#  define EPROVIDERFAILEDINIT	WSAEPROVIDERFAILEDINIT
-#endif
-#ifndef EREFUSED
-#  define EREFUSED		WSAEREFUSED
-#endif
+
+/* EINVALIDPROCTABLE is not an errno.h value at all */
+/* EINVALIDPROVIDER is not an errno.h value at all */
+/* EPROVIDERFAILEDINIT is not an errno.h value at all */
+/* EREFUSED is not an errno.h value at all */
 
 #endif /* _INC_SYS_ERRNO2 */
diff --git a/win32/win32sck.c b/win32/win32sck.c
index be51a2b243..f065be88f7 100644
--- a/win32/win32sck.c
+++ b/win32/win32sck.c
@@ -61,12 +61,15 @@ EndSockets(void)
 	WSACleanup();
 }
 
-/* Translate WSAExxx values to corresponding Exxx values. Not all WSAExxx
- * constants have corresponding Exxx constants in <errno.h> (even in VC++
- * 2010 and above, which have expanded <errno.h> with more values), but any
- * missing constants are provided by win32/include/sys/errno2.h.
+/* Translate WSAExxx values to corresponding Exxx values where possible. Not all
+ * WSAExxx constants have corresponding Exxx constants in <errno.h> (even in
+ * VC++ 2010 and above, which have expanded <errno.h> with more values), but
+ * most missing constants are provided by win32/include/sys/errno2.h. The few
+ * that are not are returned unchanged.
+ *
  * The list of possible WSAExxx values used here comes from the MSDN page
  * titled "Windows Sockets Error Codes".
+ *
  * (Note: Only the WSAExxx values are handled here; other WSAxxx values are
  * returned unchanged. The return value normally ends up in errno/$! and at
  * the Perl code level may be tested against the Exxx constants exported by
@@ -148,7 +151,7 @@ convert_wsa_error_to_errno(int wsaerr)
     case WSAENAMETOOLONG:
 	return ENAMETOOLONG;
     case WSAEHOSTDOWN:
-	return EHOSTDOWN;
+	return WSAEHOSTDOWN;		/* EHOSTDOWN is not defined */
     case WSAEHOSTUNREACH:
 	return EHOSTUNREACH;
     case WSAENOTEMPTY:
@@ -164,19 +167,19 @@ convert_wsa_error_to_errno(int wsaerr)
     case WSAEREMOTE:
 	return EREMOTE;
     case WSAEDISCON:
-	return EDISCON;
+	return WSAEDISCON;		/* EDISCON is not defined */
     case WSAENOMORE:
-	return ENOMORE;
+	return WSAENOMORE;		/* ENOMORE is not defined */
     case WSAECANCELLED:
 	return ECANCELED;
     case WSAEINVALIDPROCTABLE:
-	return EINVALIDPROCTABLE;
+	return WSAEINVALIDPROCTABLE;	/* EINVALIDPROCTABLE is not defined */
     case WSAEINVALIDPROVIDER:
-	return EINVALIDPROVIDER;
+	return WSAEINVALIDPROVIDER;	/* EINVALIDPROVIDER is not defined */
     case WSAEPROVIDERFAILEDINIT:
-	return EPROVIDERFAILEDINIT;
+	return WSAEPROVIDERFAILEDINIT;	/* EPROVIDERFAILEDINIT is not defined */
     case WSAEREFUSED:
-	return EREFUSED;
+	return WSAEREFUSED;		/* EREFUSED is not defined */
     }
 
     return wsaerr;