diff --git src/ca/client/udpiiu.cpp src/ca/client/udpiiu.cpp
index beae075..ccb2556 100644
--- src/ca/client/udpiiu.cpp
+++ src/ca/client/udpiiu.cpp
@@ -165,7 +165,7 @@ udpiiu::udpiiu (
 
 #ifdef IP_ADD_MEMBERSHIP
     {
-        int flag = 1;
+        osiSockOptMcastLoop_t flag = 1;
         if ( setsockopt ( this->sock, IPPROTO_IP, IP_MULTICAST_LOOP,
                           (char *) &flag, sizeof ( flag ) ) == -1 ) {
             char sockErrBuf[64];
diff --git src/ioc/rsrv/caservertask.c src/ioc/rsrv/caservertask.c
index 50bc650..fda4421 100644
--- src/ioc/rsrv/caservertask.c
+++ src/ioc/rsrv/caservertask.c
@@ -308,7 +308,7 @@ void rsrv_build_addr_lists(void)
         }
 #ifdef IP_ADD_MEMBERSHIP
         {
-            int flag = 1;
+            osiSockOptMcastLoop_t flag = 1;
             if (setsockopt(beaconSocket, IPPROTO_IP, IP_MULTICAST_LOOP,
                            (char *)&flag, sizeof(flag))<0) {
                 char sockErrBuf[64];
diff --git src/libCom/osi/os/Darwin/osdSock.h src/libCom/osi/os/Darwin/osdSock.h
index 1d4556e..e7c3440 100644
--- src/libCom/osi/os/Darwin/osdSock.h
+++ src/libCom/osi/os/Darwin/osdSock.h
@@ -31,6 +31,7 @@ typedef int                     SOCKET;
 #define socket_ioctl(A,B,C)     ioctl(A,B,C)
 typedef int osiSockIoctl_t;
 typedef socklen_t osiSocklen_t;
+typedef int osiSockOptMcastLoop_t;
 
 #define FD_IN_FDSET(FD) ((FD)<FD_SETSIZE)
 
diff --git src/libCom/osi/os/Linux/osdSock.h src/libCom/osi/os/Linux/osdSock.h
index 614f3f9..7164a54 100644
--- src/libCom/osi/os/Linux/osdSock.h
+++ src/libCom/osi/os/Linux/osdSock.h
@@ -35,6 +35,7 @@ typedef int                     SOCKET;
 #define socket_ioctl(A,B,C)     ioctl(A,B,C)
 typedef int osiSockIoctl_t;
 typedef socklen_t osiSocklen_t;
+typedef int osiSockOptMcastLoop_t;
 
 #define FD_IN_FDSET(FD) ((FD)<FD_SETSIZE)
 
diff --git src/libCom/osi/os/RTEMS/osdSock.h src/libCom/osi/os/RTEMS/osdSock.h
index 930ed0e..6177c30 100644
--- src/libCom/osi/os/RTEMS/osdSock.h
+++ src/libCom/osi/os/RTEMS/osdSock.h
@@ -42,6 +42,7 @@ typedef int                     SOCKET;
 #define socket_ioctl(A,B,C)     ioctl(A,B,C)
 typedef int osiSockIoctl_t;
 typedef socklen_t osiSocklen_t;
+typedef char osiSockOptMcastLoop_t;
 
 #define FD_IN_FDSET(FD) ((FD)<FD_SETSIZE)
 
diff --git src/libCom/osi/os/WIN32/osdSock.h src/libCom/osi/os/WIN32/osdSock.h
index d92e187..2ff23c4 100644
--- src/libCom/osi/os/WIN32/osdSock.h
+++ src/libCom/osi/os/WIN32/osdSock.h
@@ -28,6 +28,7 @@
 #define socket_ioctl(A,B,C)	ioctlsocket(A,B,C)
 typedef u_long FAR osiSockIoctl_t;
 typedef int osiSocklen_t;
+typedef BOOL osiSockOptMcastLoop_t;
 
 #ifndef SHUT_RD
 #   define SHUT_RD SD_RECEIVE
diff --git src/libCom/osi/os/cygwin32/osdSock.h src/libCom/osi/os/cygwin32/osdSock.h
index d642cad..75288c8 100644
--- src/libCom/osi/os/cygwin32/osdSock.h
+++ src/libCom/osi/os/cygwin32/osdSock.h
@@ -34,6 +34,7 @@ typedef int                     SOCKET;
 #define socket_ioctl(A,B,C)     ioctl(A,B,C)
 typedef int osiSockIoctl_t;
 typedef int osiSocklen_t;
+typedef int osiSockOptMcastLoop_t;
 #define FD_IN_FDSET(FD) ((FD)<FD_SETSIZE&&(FD)>=0)
 #ifndef SHUT_RD
 #define SHUT_RD 0
diff --git src/libCom/osi/os/freebsd/osdSock.h src/libCom/osi/os/freebsd/osdSock.h
index fe28d4c..b402ec1 100644
--- src/libCom/osi/os/freebsd/osdSock.h
+++ src/libCom/osi/os/freebsd/osdSock.h
@@ -36,6 +36,7 @@ typedef int                     SOCKET;
 #define socket_ioctl(A,B,C)     ioctl(A,B,C)
 typedef int osiSockIoctl_t;
 typedef socklen_t osiSocklen_t;
+typedef int osiSockOptMcastLoop_t;
 
 #define FD_IN_FDSET(FD) ((FD)<FD_SETSIZE)
 
diff --git src/libCom/osi/os/iOS/osdSock.h src/libCom/osi/os/iOS/osdSock.h
index 0b3b3f6..08849a8 100644
--- src/libCom/osi/os/iOS/osdSock.h
+++ src/libCom/osi/os/iOS/osdSock.h
@@ -32,6 +32,7 @@ typedef int                     SOCKET;
 #define socket_ioctl(A,B,C)     ioctl(A,B,C)
 typedef int osiSockIoctl_t;
 typedef socklen_t osiSocklen_t;
+typedef int osiSockOptMcastLoop_t;
 
 #define FD_IN_FDSET(FD) ((FD)<FD_SETSIZE)
 
diff --git src/libCom/osi/os/solaris/osdSock.h src/libCom/osi/os/solaris/osdSock.h
index a39c6c3..872a08d 100644
--- src/libCom/osi/os/solaris/osdSock.h
+++ src/libCom/osi/os/solaris/osdSock.h
@@ -42,6 +42,7 @@ typedef int osiSockIoctl_t;
 #else
     typedef int osiSocklen_t;
 #endif
+typedef int osiSockOptMcastLoop_t;
 
 #define DOES_NOT_ACCEPT_ZERO_LENGTH_UDP
 
diff --git src/libCom/osi/os/vxWorks/osdSock.h src/libCom/osi/os/vxWorks/osdSock.h
index 80464ef..d949b25 100644
--- src/libCom/osi/os/vxWorks/osdSock.h
+++ src/libCom/osi/os/vxWorks/osdSock.h
@@ -65,6 +65,7 @@ typedef int                     SOCKET;
 #define socket_ioctl(A,B,C)     ioctl(A,B,(int)C)
 typedef int osiSockIoctl_t;
 typedef int osiSocklen_t;
+typedef int osiSockOptMcastLoop_t;
 
 #define FD_IN_FDSET(FD) ((FD)<FD_SETSIZE&&(FD)>=0)