Document the bad assumptions currently breaking

the Socket.t tests 10, 11, and 13 in UNICOS.

p4raw-id: //depot/perl@11919

diff --git a/ext/Socket/Socket.xs b/ext/Socket/Socket.xs
index b048e59..ba8c221 100644 (file)
--- a/ext/Socket/Socket.xs
+++ b/ext/Socket/Socket.xs
@@ -217,6 +217,33 @@ inet_ntoa(ip_address_sv)
        if (DO_UTF8(ip_address_sv) && !sv_utf8_downgrade(ip_address_sv, 1))
             croak("Wide character in Socket::inet_ntoa");
        ip_address = SvPV(ip_address_sv,addrlen);
+       /* Bad assumptions here.
+        *
+        * Bad Assumption 1: struct in_addr has no other fields than
+        * the s_addr (which is the field we really care about here).
+        *
+        * Bad Assumption 2: the s_addr field is the first field
+        * in struct in_addr (the Copy() assumes that).
+        *
+        * Bad Assumption 3: the s_addr field is a simple type
+        * (such as an int).  It can be a bit field, in which
+        * case using & (address-of) on it or taking sizeof()
+        * wouldn't go over too well.  (Those are not attempted
+        * now but in case someone thinks to fix the below uses
+        * of addr (both in the length check and the Copy())
+        * by using addr.s_addr.
+        *
+        * These bad assumptions currently break UNICOS which has
+        * struct in_addr struct { u_long  st_addr:32; } s_da;
+        * #define s_addr          s_da.st_addr   
+        *
+        * and u_long is 64 bits.
+        *
+        * The bold soul attempting to fix this should also
+        * fix pack_sockaddr_in() to agree.
+        *
+        * --jhi
+        */
        if (addrlen != sizeof(addr)) {
            croak("Bad arg length for %s, length is %d, should be %d",
                        "Socket::inet_ntoa",