interrupted system call interface

src/libCom/osi/osiSock.c

@@ -21,6 +21,7 @@
 
 #define epicsExportSharedSymbols
 #include "epicsAssert.h"
+#include "epicsSignal.h"
 #include "osiSock.h"
 
 #define nDigitsDottedIP 4u
@@ -167,3 +168,14 @@ void epicsShareAPI ipAddrToDottedIP
     }
 }
 
+epicsShareFunc void epicsShareAPI epicsSocketEnableInterruptedSystemCall ()
+{
+    epicsSignalInstallSigUrgIgnore ();
+}
+
+epicsShareFunc void epicsShareAPI epicsSocketInterruptSystemCall 
+                                    ( struct epicsThreadOSD * threadId )
+{
+    epicsSignalRaiseSigUrg ( threadId );
+}
+

src/libCom/osi/osiSock.h

@@ -166,6 +166,16 @@ epicsShareFunc void epicsShareAPI osiSockDiscoverBroadcastAddresses
  */
 epicsShareFunc osiSockAddr epicsShareAPI osiLocalAddr (SOCKET socket);
 
+
+/*
+ * Certain os, such as HPUX, do not unblock a socket system call 
+ * when another thread asynchronously calls both shutdown() and 
+ * close(). To solve this problem we need to employ OS specific
+ * mechanisms.
+ */
+epicsShareFunc void epicsShareAPI epicsSocketEnableInterruptedSystemCall ();
+epicsShareFunc void epicsShareAPI epicsSocketInterruptSystemCall ( struct epicsThreadOSD * );
+
 #ifdef __cplusplus
 }
 #endif