[vtkusers] Problem in "vtkSocketCommunicator" (Windows XP)

[Markus Neff]

Dear VTK-Team,

on Windows XP, I have problems to send very large objects (in my case
of the class "vtkImageData") by calling
vtkSocketCommunicator::Send(...). The problem seems to be that the
respective OS "send()" call fails with the error code "WSAENOBUFS".

According to the documentation this indicates that "an operation on a
socket could not be performed because the system lacked sufficient
buffer space or because a queue was full."

I didn't try if other OS have comparable problems but it should not
hurt to hand the data to the network-layer in smaller
chunks. Therefore I suggest the patch below.

Best wishes,
Markus



============================== patch start =================================

--- vtkSocketCommunicator.1.40.cxx	2003-05-20 10:25:15.000000000 +0200
+++ vtkSocketCommunicator.cxx	2003-05-20 13:45:22.000000000 +0200
@@ -36,6 +36,8 @@ PURPOSE.  See the above copyright notice
 #define vtkCloseSocketMacro(sock) (close(sock))
 #endif
 
+#define MAXSNDRCV 64 * 1024
+
 vtkCxxRevisionMacro(vtkSocketCommunicator, "$Revision: 1.40 $");
 vtkStandardNewMacro(vtkSocketCommunicator);
 
@@ -424,7 +426,9 @@ int vtkSocketCommunicator::SendInternal(
   int total = 0;
   do
     {
-    int n = send(socket, buffer+total, length-total, 0);
+    int remainder = length - total;
+    int sendnow   = (remainder < MAXSNDRCV) ? remainder : MAXSNDRCV;
+    int n = send(socket, buffer+total, sendnow, 0);
     if(n < 1)
       {
       return 0;
@@ -441,7 +445,9 @@ int vtkSocketCommunicator::ReceiveIntern
   int total = 0;
   do
     {
-    int n = recv(socket, buffer+total, length-total, 0);
+    int remainder = length - total;
+    int recvnow   = (remainder < MAXSNDRCV) ? remainder : MAXSNDRCV;
+    int n = recv(socket, buffer+total, recvnow, 0);
     if(n < 1)
       {
       return 0;

============================== patch end =================================