minor review changes

Signed-off-by: Jake Smith <[email protected]>

system/jlib/jsocket.cpp

@@ -666,6 +666,7 @@ static win_socket_library ws32_lib;
 #define JSE_NOTSOCK WSAENOTSOCK
 #define JSE_TIMEDOUT WSAETIMEDOUT
 #define JSE_CONNREFUSED WSAECONNREFUSED
+#define JSE_EAGAIN WSAEWOULDBLOCK
 #define JSE_BADF WSAEBADF
 
 #define JSE_INTR WSAEINTR
@@ -785,6 +786,7 @@ int inet_aton (const char *name, struct in_addr *addr)
 #define JSE_NOTSOCK ENOTSOCK
 #define JSE_TIMEDOUT ETIMEDOUT
 #define JSE_CONNREFUSED ECONNREFUSED
+#define JSE_EAGAIN EAGAIN
 #define JSE_BADF EBADF
 
 
@@ -1982,7 +1984,7 @@ void CSocket::readtms(void* buf, size32_t min_size, size32_t max_size, size32_t
                 }
                 else
                 {
-                    if (err == JSE_WOULDBLOCK || err == EAGAIN) // if EGAIN or EWOULDBLOCK - no more data to read
+                    if (err == JSE_WOULDBLOCK || err == JSE_EAGAIN) // if EAGAIN or EWOULDBLOCK - no more data to read
                     {
                         //NB: in UDP can only reach here if have not read anything so far.
 
@@ -2138,7 +2140,7 @@ size32_t CSocket::writetms(void const* buf, size32_t minSize, size32_t size, uns
                     errclose();
                     err = JSOCKERR_broken_pipe;
                 }
-                if (err == JSE_WOULDBLOCK)
+                if (err == JSE_WOULDBLOCK || err == JSE_EAGAIN)
                 {
                     if (sizeWritten >= minSize)
                         break;
@@ -7242,6 +7244,12 @@ extern jlib_decl void shutdownAndCloseNoThrow(ISocket * optSocket)
 ////
 void ScopedNonBlockingMode::init(ISocket *_socket)
 {
+    // NB: for the time being, don't switch to non-blocking mode for UDP connections (may want to revisit).
+    // It probably does make sense, e.g. to allow readtms/writetms to be called with min_size 0 and return if blocked,
+    // but we don't depend on it at the moment, and to reduce the impact of these semantic changes, leave UDP as blocking for now.
+    // It would likely be necessary if UDP+SSL were ever in play.
+    if (socket->connectionless())
+        return;
     socket = _socket;
     if (socket->set_nonblock(true)) // was already nonblocking
         socket = nullptr; // nothing to reset in dtor