From 62c3b0a585a4abcaae7794e487627bea29712be8 Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Tue, 27 Aug 2019 16:51:00 +0200
Subject: [PATCH 01/23] don't send errlog on all logClients

---
 modules/libcom/src/log/iocLog.c    | 14 ++++++++++++++
 modules/libcom/src/log/logClient.c |  4 ----
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/modules/libcom/src/log/iocLog.c b/modules/libcom/src/log/iocLog.c
index e62da2050..8cb1349a1 100644
--- a/modules/libcom/src/log/iocLog.c
+++ b/modules/libcom/src/log/iocLog.c
@@ -18,8 +18,10 @@
 
 #define epicsExportSharedSymbols
 #include "envDefs.h"
+#include "errlog.h"
 #include "logClient.h"
 #include "iocLog.h"
+#include "epicsExit.h"
 
 int iocLogDisable = 0;
 
@@ -74,6 +76,14 @@ void epicsShareAPI epicsShareAPI iocLogFlush (void)
     }
 }
 
+/*
+ * logClientDestroy()
+ */
+static void iocLogClientDestroy (logClientId id)
+{
+    errlogRemoveListeners (logClientSendMessage, id);
+}
+
 /*
  *  iocLogClientInit()
  */
@@ -89,6 +99,10 @@ static logClientId iocLogClientInit (void)
         return NULL;
     }
     id = logClientCreate (addr, port);
+    if (id != NULL) {
+        errlogAddListener (logClientSendMessage, id);
+        epicsAtExit (iocLogClientDestroy, id);
+    }
     return id;
 }
 
diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 99ee671d9..b076d50cb 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -154,8 +154,6 @@ static void logClientDestroy (logClientId id)
         return;
     }
 
-    errlogRemoveListeners ( logClientSendMessage, (void *) pClient );
-
     logClientClose ( pClient );
 
     epicsMutexDestroy ( pClient->mutex );
@@ -549,8 +547,6 @@ logClientId epicsShareAPI logClientCreate (
             pClient->name, LOG_SERVER_CREATE_CONNECT_SYNC_TIMEOUT );
     }
         
-    errlogAddListener ( logClientSendMessage, (void *) pClient );
-
     return (void *) pClient;
 }
 

From 243287877311748057baa61937ea8d8a530f8d27 Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Tue, 27 Aug 2019 17:34:01 +0200
Subject: [PATCH 02/23] speed up logRestart thread termination at exit

---
 modules/libcom/src/log/logClient.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index b076d50cb..96382a2eb 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -44,6 +44,7 @@ typedef struct {
     SOCKET              sock;
     epicsThreadId       restartThreadId;
     epicsEventId        stateChangeNotify;
+    epicsEventId        shutdownNotify;
     unsigned            connectCount;
     unsigned            nextMsgIndex;
     unsigned            connected;
@@ -113,6 +114,7 @@ static void logClientDestroy (logClientId id)
     epicsMutexMustLock ( pClient->mutex );
     pClient->shutdown = 1u;
     epicsMutexUnlock ( pClient->mutex );
+    epicsEventSignal ( pClient->shutdownNotify );
 
     /* unblock log client thread blocking in send() or connect() */
     interruptInfo =
@@ -157,8 +159,8 @@ static void logClientDestroy (logClientId id)
     logClientClose ( pClient );
 
     epicsMutexDestroy ( pClient->mutex );
-   
     epicsEventDestroy ( pClient->stateChangeNotify );
+    epicsEventDestroy ( pClient->shutdownNotify );
 
     free ( pClient );
 }
@@ -461,8 +463,8 @@ static void logClientRestart ( logClientId id )
         else {
             logClientConnect ( pClient );
         }
-        
-        epicsThreadSleep ( LOG_RESTART_DELAY );
+
+        epicsEventWaitWithTimeout ( pClient->shutdownNotify, LOG_RESTART_DELAY);
 
         epicsMutexMustLock ( pClient->mutex );
     }
@@ -505,14 +507,22 @@ logClientId epicsShareAPI logClientCreate (
     pClient->shutdownConfirm = 0;
 
     epicsAtExit (logClientDestroy, (void*) pClient);
-    
+
     pClient->stateChangeNotify = epicsEventCreate (epicsEventEmpty);
     if ( ! pClient->stateChangeNotify ) {
         epicsMutexDestroy ( pClient->mutex );
         free ( pClient );
         return NULL;
     }
-   
+
+    pClient->shutdownNotify = epicsEventCreate (epicsEventEmpty);
+    if ( ! pClient->shutdownNotify ) {
+        epicsMutexDestroy ( pClient->mutex );
+        epicsEventDestroy ( pClient->stateChangeNotify );
+        free ( pClient );
+        return NULL;
+    }
+
     pClient->restartThreadId = epicsThreadCreate (
         "logRestart", epicsThreadPriorityLow, 
         epicsThreadGetStackSize(epicsThreadStackSmall),
@@ -520,6 +530,7 @@ logClientId epicsShareAPI logClientCreate (
     if ( pClient->restartThreadId == NULL ) {
         epicsMutexDestroy ( pClient->mutex );
         epicsEventDestroy ( pClient->stateChangeNotify );
+        epicsEventDestroy ( pClient->shutdownNotify );
         free (pClient);
         fprintf(stderr, "log client: unable to start log client connection watch dog thread\n");
         return NULL;

From 0a3427c835e367792dd3419bc2a5bc1aea02386a Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Wed, 28 Aug 2019 09:29:57 +0200
Subject: [PATCH 03/23] do not discard unsent messages when log server has
 closed connection, instead try to send them after reconnect

---
 modules/libcom/src/log/logClient.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 96382a2eb..75984404c 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -85,8 +85,6 @@ static void logClientClose ( logClient *pClient )
         pClient->sock = INVALID_SOCKET;
     }
 
-    pClient->nextMsgIndex = 0u;
-    memset ( pClient->msgBuf, '\0', sizeof ( pClient->msgBuf ) );
     pClient->connected = 0u;
 
     /*

From 709208ef5cd4db2764875175aacd94fd500e984a Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Wed, 28 Aug 2019 11:41:12 +0200
Subject: [PATCH 04/23] elimitate duplicate code in logClient

---
 modules/libcom/src/log/logClient.c | 62 +++++++-----------------------
 1 file changed, 14 insertions(+), 48 deletions(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 75984404c..90fde98b5 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -174,57 +174,23 @@ static void sendMessageChunk(logClient * pClient, const char * message) {
         unsigned msgBufBytesLeft = 
             sizeof ( pClient->msgBuf ) - pClient->nextMsgIndex;
 
-        if ( strSize > msgBufBytesLeft ) {
-            int status;
-
-            if ( ! pClient->connected ) {
-                break;
-            }
-
-            if ( msgBufBytesLeft > 0u ) {
-                memcpy ( & pClient->msgBuf[pClient->nextMsgIndex],
-                    message, msgBufBytesLeft );
-                pClient->nextMsgIndex += msgBufBytesLeft;
-                strSize -= msgBufBytesLeft;
-                message += msgBufBytesLeft;
-            }
-
-            status = send ( pClient->sock, pClient->msgBuf, 
-                pClient->nextMsgIndex, 0 );
-            if ( status > 0 ) {
-                unsigned nSent = (unsigned) status;
-                if ( nSent < pClient->nextMsgIndex ) {
-                    unsigned newNextMsgIndex = pClient->nextMsgIndex - nSent;
-                    memmove ( pClient->msgBuf, & pClient->msgBuf[nSent], 
-                        newNextMsgIndex );
-                    pClient->nextMsgIndex = newNextMsgIndex;
-                }
-                else {
-                    pClient->nextMsgIndex = 0u;
-                }
-            }
-            else {
-                if ( ! pClient->shutdown ) {
-                    char sockErrBuf[64];
-                    if ( status ) {
-                        epicsSocketConvertErrnoToString ( sockErrBuf, sizeof ( sockErrBuf ) );
-                    }
-                    else {
-                        strcpy ( sockErrBuf, "server initiated disconnect" );
-                    }
-                    fprintf ( stderr, "log client: lost contact with log server at \"%s\" because \"%s\"\n", 
-                        pClient->name, sockErrBuf );
-                }
-                logClientClose ( pClient );
-                break;
-            }
+        if ( msgBufBytesLeft < strSize && pClient->nextMsgIndex != 0u && pClient->connected)
+        {
+            /* buffer is full, thus flush it */
+            logClientFlush ( pClient );
+            msgBufBytesLeft = sizeof ( pClient->msgBuf ) - pClient->nextMsgIndex;
         }
-        else {
-            memcpy ( & pClient->msgBuf[pClient->nextMsgIndex],
-                message, strSize );
-            pClient->nextMsgIndex += strSize;
+        if ( msgBufBytesLeft == 0u ) {
+            fprintf ( stderr, "log client: messages to \"%s\" are lost\n",
+                pClient->name );
             break;
         }
+        if ( msgBufBytesLeft > strSize) msgBufBytesLeft = strSize;
+        memcpy ( & pClient->msgBuf[pClient->nextMsgIndex],
+            message, msgBufBytesLeft );
+        pClient->nextMsgIndex += msgBufBytesLeft;
+        strSize -= msgBufBytesLeft;
+        message += msgBufBytesLeft;
     }
 }
 

From 59aa9cfe746b3fc08d7b94b82f47973f6c5ed92c Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Wed, 28 Aug 2019 15:15:19 +0200
Subject: [PATCH 05/23] avoid needless memmove calls

---
 modules/libcom/src/log/logClient.c | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 90fde98b5..203f29dd3 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -219,6 +219,8 @@ void epicsShareAPI logClientSend ( logClientId id, const char * message )
 
 void epicsShareAPI logClientFlush ( logClientId id )
 {
+    unsigned nSent = 0u;
+
     logClient * pClient = ( logClient * ) id;
 
     if ( ! pClient ) {
@@ -227,20 +229,11 @@ void epicsShareAPI logClientFlush ( logClientId id )
 
     epicsMutexMustLock ( pClient->mutex );
 
-    while ( pClient->nextMsgIndex && pClient->connected ) {
-        int status = send ( pClient->sock, pClient->msgBuf, 
-            pClient->nextMsgIndex, 0 );
+    while ( nSent < pClient->nextMsgIndex && pClient->connected ) {
+        int status = send ( pClient->sock, pClient->msgBuf + nSent,
+            pClient->nextMsgIndex - nSent, 0 );
         if ( status > 0 ) {
-            unsigned nSent = (unsigned) status;
-            if ( nSent < pClient->nextMsgIndex ) {
-                unsigned newNextMsgIndex = pClient->nextMsgIndex - nSent;
-                memmove ( pClient->msgBuf, & pClient->msgBuf[nSent], 
-                    newNextMsgIndex );
-                pClient->nextMsgIndex = newNextMsgIndex;
-            }
-            else {
-                pClient->nextMsgIndex = 0u;
-            }
+            nSent += (unsigned) status;
         }
         else {
             if ( ! pClient->shutdown ) {
@@ -258,6 +251,11 @@ void epicsShareAPI logClientFlush ( logClientId id )
             break;
         }
     }
+    pClient->nextMsgIndex -= nSent;
+    if ( nSent > 0 && pClient->nextMsgIndex > 0 ) {
+        memmove ( pClient->msgBuf, & pClient->msgBuf[nSent],
+            pClient->nextMsgIndex );
+    }
     epicsMutexUnlock ( pClient->mutex );
 }
 

From 9df98c18386f1204fdf21a58f0f6dc1aae04126e Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Wed, 28 Aug 2019 15:23:00 +0200
Subject: [PATCH 06/23] send pending log messages directly after connecting

---
 modules/libcom/src/log/logClient.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 203f29dd3..743910fb8 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -223,7 +223,7 @@ void epicsShareAPI logClientFlush ( logClientId id )
 
     logClient * pClient = ( logClient * ) id;
 
-    if ( ! pClient ) {
+    if ( ! pClient || ! pClient->connected ) {
         return;
     }
 
@@ -419,12 +419,8 @@ static void logClientRestart ( logClientId id )
 
         epicsMutexUnlock ( pClient->mutex );
 
-        if ( isConn ) {
-            logClientFlush ( pClient );
-        }
-        else {
-            logClientConnect ( pClient );
-        }
+        if ( ! isConn ) logClientConnect ( pClient );
+        logClientFlush ( pClient );
 
         epicsEventWaitWithTimeout ( pClient->shutdownNotify, LOG_RESTART_DELAY);
 

From 2b0161d9bfd8fc604942996d1812d245bf4a00f7 Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Wed, 28 Aug 2019 15:29:23 +0200
Subject: [PATCH 07/23] no need to delay startup only because log server is
 currently not available

---
 modules/libcom/src/log/logClient.c | 25 -------------------------
 1 file changed, 25 deletions(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 743910fb8..72a2e1364 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -54,7 +54,6 @@ typedef struct {
 } logClient;
 
 static const double      LOG_RESTART_DELAY = 5.0; /* sec */
-static const double      LOG_SERVER_CREATE_CONNECT_SYNC_TIMEOUT = 5.0; /* sec */
 static const double      LOG_SERVER_SHUTDOWN_TIMEOUT = 30.0; /* sec */
 
 /*
@@ -438,9 +437,7 @@ static void logClientRestart ( logClientId id )
 logClientId epicsShareAPI logClientCreate (
     struct in_addr server_addr, unsigned short server_port)
 {
-    epicsTimeStamp begin, current;
     logClient *pClient;
-    double diff;
 
     pClient = calloc (1, sizeof (*pClient));
     if (pClient==NULL) {
@@ -494,28 +491,6 @@ logClientId epicsShareAPI logClientCreate (
         return NULL;
     }
 
-    /*
-     * attempt to synchronize with circuit connect
-     */
-    epicsTimeGetCurrent ( & begin );
-    epicsMutexMustLock ( pClient->mutex );
-    do {
-        epicsMutexUnlock ( pClient->mutex );
-        epicsEventWaitWithTimeout ( 
-            pClient->stateChangeNotify, 
-            LOG_SERVER_CREATE_CONNECT_SYNC_TIMEOUT / 10.0 ); 
-        epicsTimeGetCurrent ( & current );
-        diff = epicsTimeDiffInSeconds ( & current, & begin );
-        epicsMutexMustLock ( pClient->mutex );
-    }
-    while ( ! pClient->connected && diff < LOG_SERVER_CREATE_CONNECT_SYNC_TIMEOUT );
-    epicsMutexUnlock ( pClient->mutex );
-
-    if ( ! pClient->connected ) {
-        fprintf (stderr, "log client create: timed out synchronizing with circuit connect to \"%s\" after %.1f seconds\n",
-            pClient->name, LOG_SERVER_CREATE_CONNECT_SYNC_TIMEOUT );
-    }
-        
     return (void *) pClient;
 }
 

From 49bf8bb5ec900c503f4c5df7f5f73df203503e7e Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Tue, 17 Sep 2019 11:59:02 +0200
Subject: [PATCH 08/23] removed unneeded include

---
 modules/libcom/src/log/logClient.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 72a2e1364..723f5d4be 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -25,7 +25,6 @@
 #include "dbDefs.h"
 #include "epicsEvent.h"
 #include "iocLog.h"
-#include "errlog.h"
 #include "epicsMutex.h"
 #include "epicsThread.h"
 #include "epicsTime.h"

From d162337b9a52a860e6c4e079f2f147163d3f7226 Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Tue, 17 Sep 2019 14:39:03 +0200
Subject: [PATCH 09/23] improve logClientShow to show unsent bytes on level 2
 (and fix level 1)

---
 modules/libcom/src/log/logClient.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 723f5d4be..9b9e039b1 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -507,14 +507,21 @@ void epicsShareAPI logClientShow (logClientId id, unsigned level)
         printf ("log client: disconnected from log server at \"%s\"\n", pClient->name);
     }
 
-    if (level>1) {
-        printf ("log client: sock=%s, connect cycles = %u\n",
+    if (logClientPrefix) {
+        printf ("log client: prefix is \"%s\"\n", logClientPrefix);
+    }
+
+    if (level>0) {
+        printf ("log client: sock %s, connect cycles = %u\n",
             pClient->sock==INVALID_SOCKET?"INVALID":"OK",
             pClient->connectCount);
     }
-
-    if (logClientPrefix) {
-        printf ("log client: prefix is \"%s\"\n", logClientPrefix);
+    if (level>1) {
+        printf ("log client: %u bytes in buffer\n", pClient->nextMsgIndex);
+        if (pClient->nextMsgIndex)
+            printf("-------------------------\n"
+                "%.*s-------------------------\n",
+                (int)(pClient->nextMsgIndex), pClient->msgBuf);
     }
 }
 

From 26f6f674be89f209606aeb447929e8146d43e230 Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Tue, 17 Sep 2019 14:41:35 +0200
Subject: [PATCH 10/23] increase error message buffer size for long (Windows)
 error messges

---
 modules/libcom/src/log/logClient.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 9b9e039b1..3defa6baf 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -235,7 +235,7 @@ void epicsShareAPI logClientFlush ( logClientId id )
         }
         else {
             if ( ! pClient->shutdown ) {
-                char sockErrBuf[64];
+                char sockErrBuf[128];
                 if ( status ) {
                     epicsSocketConvertErrnoToString ( sockErrBuf, sizeof ( sockErrBuf ) );
                 }
@@ -274,7 +274,7 @@ static void logClientMakeSock (logClient *pClient)
      */
     pClient->sock = epicsSocketCreate ( AF_INET, SOCK_STREAM, 0 );
     if ( pClient->sock == INVALID_SOCKET ) {
-        char sockErrBuf[64];
+        char sockErrBuf[128];
         epicsSocketConvertErrnoToString ( 
             sockErrBuf, sizeof ( sockErrBuf ) );
         fprintf ( stderr, "log client: no socket error %s\n", 
@@ -326,7 +326,7 @@ static void logClientConnect (logClient *pClient)
             }
             else {
                 if ( pClient->connFailStatus != errnoCpy && ! pClient->shutdown ) {
-                    char sockErrBuf[64];
+                    char sockErrBuf[128];
                     epicsSocketConvertErrnoToString (
                         sockErrBuf, sizeof ( sockErrBuf ) );
                     fprintf (stderr,
@@ -352,7 +352,7 @@ static void logClientConnect (logClient *pClient)
     optval = TRUE;
     status = setsockopt (pClient->sock, SOL_SOCKET, SO_KEEPALIVE, (char *)&optval, sizeof(optval));
     if (status<0) {
-        char sockErrBuf[64];
+        char sockErrBuf[128];
         epicsSocketConvertErrnoToString ( 
             sockErrBuf, sizeof ( sockErrBuf ) );
         fprintf (stderr, "log client: unable to enable keepalive option because \"%s\"\n", sockErrBuf);
@@ -364,7 +364,7 @@ static void logClientConnect (logClient *pClient)
      */
     status = shutdown (pClient->sock, SHUT_RD);
     if (status < 0) {
-        char sockErrBuf[64];
+        char sockErrBuf[128];
         epicsSocketConvertErrnoToString ( 
             sockErrBuf, sizeof ( sockErrBuf ) );
         fprintf (stderr, "%s:%d shutdown(%d,SHUT_RD) error was \"%s\"\n", 
@@ -385,7 +385,7 @@ static void logClientConnect (logClient *pClient)
         lingerval.l_linger = 60*5; 
         status = setsockopt (pClient->sock, SOL_SOCKET, SO_LINGER, (char *) &lingerval, sizeof(lingerval));
         if (status<0) {
-            char sockErrBuf[64];
+            char sockErrBuf[128];
             epicsSocketConvertErrnoToString ( 
                 sockErrBuf, sizeof ( sockErrBuf ) );
             fprintf (stderr, "log client: unable to set linger options because \"%s\"\n", sockErrBuf);

From f85454a8d66e42503ae5295144ed2da8147ef4bc Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Tue, 17 Sep 2019 17:06:55 +0200
Subject: [PATCH 11/23] use dynamic debug flag for logClient

---
 modules/database/src/ioc/misc/dbCore.dbd |  3 +++
 modules/libcom/src/log/logClient.c       | 22 +++++++++++-----------
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/modules/database/src/ioc/misc/dbCore.dbd b/modules/database/src/ioc/misc/dbCore.dbd
index 51f9c9640..adde24e4f 100644
--- a/modules/database/src/ioc/misc/dbCore.dbd
+++ b/modules/database/src/ioc/misc/dbCore.dbd
@@ -33,3 +33,6 @@ variable(callbackParallelThreadsDefault,int)
 
 # Real-time operation
 variable(dbThreadRealtimeLock,int)
+
+# show logClient network activity
+variable(logClientDebug,int)
diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 3defa6baf..19d79b617 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -21,7 +21,6 @@
 #include <string.h>
 #include <stdio.h>
 
-#define epicsExportSharedSymbols
 #include "dbDefs.h"
 #include "epicsEvent.h"
 #include "iocLog.h"
@@ -32,9 +31,13 @@
 #include "epicsAssert.h"
 #include "epicsExit.h"
 #include "epicsSignal.h"
+#include "epicsExport.h"
 
 #include "logClient.h"
 
+int logClientDebug = 0;
+epicsExportAddress (int, logClientDebug);
+
 typedef struct {
     char                msgBuf[0x4000];
     struct sockaddr_in  addr;
@@ -65,10 +68,10 @@ static char* logClientPrefix = NULL;
  */
 static void logClientClose ( logClient *pClient )
 {
-#   ifdef DEBUG
+    if (logClientDebug) {
         fprintf (stderr, "log client: lingering for connection close...");
         fflush (stderr);
-#   endif
+    }
 
     /*
      * mutex on
@@ -90,9 +93,8 @@ static void logClientClose ( logClient *pClient )
      */
     epicsMutexUnlock (pClient->mutex);
 
-#   ifdef DEBUG
+    if (logClientDebug)
         fprintf (stderr, "done\n");
-#   endif
 }
 
 /*
@@ -262,10 +264,10 @@ void epicsShareAPI logClientFlush ( logClientId id )
  */
 static void logClientMakeSock (logClient *pClient)
 {
-    
-#   ifdef DEBUG
+    if (logClientDebug) {
         fprintf (stderr, "log client: creating socket...");
-#   endif
+        fflush (stderr);
+    }
 
     epicsMutexMustLock (pClient->mutex);
    
@@ -283,10 +285,8 @@ static void logClientMakeSock (logClient *pClient)
     
     epicsMutexUnlock (pClient->mutex);
 
-#   ifdef DEBUG
+    if (logClientDebug)
         fprintf (stderr, "done\n");
-#   endif
-
 }
 
 /*

From 6ffc9e17dacf7af450cdee2e3915cb73f317ef96 Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Tue, 17 Sep 2019 17:34:16 +0200
Subject: [PATCH 12/23] ask logClient socket how many bytes are still in the
 send queue and don't discard them in case the connection turns out broken.

---
 modules/libcom/src/log/logClient.c | 83 +++++++++++++++++++++---------
 1 file changed, 59 insertions(+), 24 deletions(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 19d79b617..44eaf7dab 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -49,6 +49,7 @@ typedef struct {
     epicsEventId        shutdownNotify;
     unsigned            connectCount;
     unsigned            nextMsgIndex;
+    unsigned            backlog;
     unsigned            connected;
     unsigned            shutdown;
     unsigned            shutdownConfirm;
@@ -194,6 +195,39 @@ static void sendMessageChunk(logClient * pClient, const char * message) {
     }
 }
 
+/*
+ * epicsSockCountUnsentBytes ()
+ * Should go to osd socket support
+ */
+#if defined (_WIN32) && WINVER >= _WIN32_WINNT_WIN10
+#include <mstcpip.h>
+#endif
+
+static int epicsSockCountUnsentBytes(SOCKET sock) {
+#if defined (_WIN32) && WINVER >= _WIN32_WINNT_WIN10
+/* Windows 10 Version 1703 / Server 2016 */
+/* https://docs.microsoft.com/en-us/windows/win32/api/mstcpip/ns-mstcpip-tcp_info_v0 */
+    DWORD infoVersion = 0, bytesReturned;
+    TCP_INFO_v0 tcpInfo;
+    int status;
+    if ((status = WSAIoctl(sock, SIO_TCP_INFO, &infoVersion, sizeof(infoVersion),
+        &tcpInfo, sizeof(tcpInfo), &bytesReturned, NULL, NULL)) == 0)
+        return tcpInfo.BytesInFlight;
+#elif defined (SO_NWRITE)
+/* macOS / iOS */
+/* https://www.unix.com/man-page/osx/2/setsockopt/ */
+    int unsent;
+    if (getsockopt(sock, SOL_SOCKET, SO_NWRITE, &unsent) == 0)
+        return unsent;
+#elif defined (TIOCOUTQ)
+/* Linux */
+/* https://linux.die.net/man/7/tcp */
+    int unsent;
+    if (ioctl(sock, TIOCOUTQ, &unsent) == 0)
+        return unsent;
+#endif
+    return 0;
+}
 
 /* 
  * logClientSend ()
@@ -219,7 +253,8 @@ void epicsShareAPI logClientSend ( logClientId id, const char * message )
 
 void epicsShareAPI logClientFlush ( logClientId id )
 {
-    unsigned nSent = 0u;
+    unsigned nSent;
+    int status = 0;
 
     logClient * pClient = ( logClient * ) id;
 
@@ -229,32 +264,32 @@ void epicsShareAPI logClientFlush ( logClientId id )
 
     epicsMutexMustLock ( pClient->mutex );
 
+    nSent = pClient->backlog;
     while ( nSent < pClient->nextMsgIndex && pClient->connected ) {
-        int status = send ( pClient->sock, pClient->msgBuf + nSent,
+        status = send ( pClient->sock, pClient->msgBuf + nSent,
             pClient->nextMsgIndex - nSent, 0 );
-        if ( status > 0 ) {
-            nSent += (unsigned) status;
-        }
-        else {
-            if ( ! pClient->shutdown ) {
-                char sockErrBuf[128];
-                if ( status ) {
-                    epicsSocketConvertErrnoToString ( sockErrBuf, sizeof ( sockErrBuf ) );
-                }
-                else {
-                    strcpy ( sockErrBuf, "server initiated disconnect" );
-                }
-                fprintf ( stderr, "log client: lost contact with log server at \"%s\" because \"%s\"\n", 
-                    pClient->name, sockErrBuf );
-            }
-            logClientClose ( pClient );
-            break;
-        }
+        if ( status < 0 ) break;
+        nSent += status;
     }
-    pClient->nextMsgIndex -= nSent;
-    if ( nSent > 0 && pClient->nextMsgIndex > 0 ) {
-        memmove ( pClient->msgBuf, & pClient->msgBuf[nSent],
-            pClient->nextMsgIndex );
+
+    if ( status < 0 ) {
+        if ( ! pClient->shutdown ) {
+            char sockErrBuf[128];
+            epicsSocketConvertErrnoToString ( sockErrBuf, sizeof ( sockErrBuf ) );
+            fprintf ( stderr, "log client: lost contact with log server at \"%s\" because \"%s\"\n", 
+                pClient->name, sockErrBuf );
+        }
+        pClient->backlog = 0;
+        logClientClose ( pClient );
+    }
+    else if ( nSent > 0 && pClient->nextMsgIndex > 0 ) {
+        pClient->backlog = epicsSockCountUnsentBytes ( pClient->sock );
+        nSent -= pClient->backlog;
+        if ( nSent > 0 ) {
+            memmove ( pClient->msgBuf, & pClient->msgBuf[nSent],
+                pClient->nextMsgIndex );
+            pClient->nextMsgIndex -= nSent;
+        }
     }
     epicsMutexUnlock ( pClient->mutex );
 }

From 931054d4fd96d0896bb74c2765c731bbbcef7295 Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Tue, 17 Sep 2019 17:45:33 +0200
Subject: [PATCH 13/23] cannot print sockets with %d in Windows, they are not
 small ints but maybe pointers.

---
 modules/libcom/src/log/logClient.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 44eaf7dab..762703417 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -402,8 +402,8 @@ static void logClientConnect (logClient *pClient)
         char sockErrBuf[128];
         epicsSocketConvertErrnoToString ( 
             sockErrBuf, sizeof ( sockErrBuf ) );
-        fprintf (stderr, "%s:%d shutdown(%d,SHUT_RD) error was \"%s\"\n", 
-            __FILE__, __LINE__, pClient->sock, sockErrBuf);
+        fprintf (stderr, "%s:%d shutdown(sock,SHUT_RD) error was \"%s\"\n", 
+            __FILE__, __LINE__, sockErrBuf);
         /* not fatal (although it shouldn't happen) */
     }
 

From c9b670977d590fb95455c358ed5597599804d66a Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Wed, 18 Sep 2019 09:58:28 +0200
Subject: [PATCH 14/23] sending 0 bytes helps to detect broken connections on
 some systems (but is undefined behavior on Linux, fails on vxWorks and is a
 documented no-op on Windows)

---
 modules/libcom/src/log/logClient.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 762703417..6671d2785 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -272,6 +272,15 @@ void epicsShareAPI logClientFlush ( logClientId id )
         nSent += status;
     }
 
+    if ( pClient->backlog > 0 && status >= 0 )
+    {
+        /* On Linux send 0 bytes can detect EPIPE */
+        /* NOOP on Windows, fails on vxWorks */
+        errno = 0;
+        status = send ( pClient->sock, NULL, 0, 0 );
+        if (!(errno == ECONNRESET || errno == EPIPE)) status = 0;
+    }
+
     if ( status < 0 ) {
         if ( ! pClient->shutdown ) {
             char sockErrBuf[128];

From db3b160f4ec7eeb988aa585078740b1c2aa7f8a7 Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Thu, 19 Sep 2019 08:54:19 +0200
Subject: [PATCH 15/23] fix wrong function name in comment

---
 modules/libcom/src/log/iocLog.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/libcom/src/log/iocLog.c b/modules/libcom/src/log/iocLog.c
index 8cb1349a1..c0fa33fa6 100644
--- a/modules/libcom/src/log/iocLog.c
+++ b/modules/libcom/src/log/iocLog.c
@@ -77,7 +77,7 @@ void epicsShareAPI epicsShareAPI iocLogFlush (void)
 }
 
 /*
- * logClientDestroy()
+ * iocLogClientDestroy()
  */
 static void iocLogClientDestroy (logClientId id)
 {

From 64f540a64ffc3282d05b3a6b7274e63639f1116c Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Thu, 19 Sep 2019 10:44:36 +0200
Subject: [PATCH 16/23] moved logClientSendMessage and made it static

---
 modules/libcom/src/log/iocLog.c    | 11 +++++++++++
 modules/libcom/src/log/logClient.c | 10 ----------
 modules/libcom/src/log/logClient.h |  1 -
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/modules/libcom/src/log/iocLog.c b/modules/libcom/src/log/iocLog.c
index c0fa33fa6..ba78041c8 100644
--- a/modules/libcom/src/log/iocLog.c
+++ b/modules/libcom/src/log/iocLog.c
@@ -76,6 +76,16 @@ void epicsShareAPI epicsShareAPI iocLogFlush (void)
     }
 }
 
+/*
+ * logClientSendMessage ()
+ */
+static void logClientSendMessage ( logClientId id, const char * message )
+{
+    if ( !iocLogDisable ) {
+        logClientSend (id, message);
+    }
+}
+
 /*
  * iocLogClientDestroy()
  */
@@ -149,3 +159,4 @@ logClientId epicsShareAPI logClientInit (void)
 {
     return iocLogClientInit ();
 }
+
diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 6671d2785..cd832b60c 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -569,16 +569,6 @@ void epicsShareAPI logClientShow (logClientId id, unsigned level)
     }
 }
 
-/*
- * logClientSendMessage (); deprecated
- */
-void logClientSendMessage ( logClientId id, const char * message )
-{
-    if ( !iocLogDisable ) {
-        logClientSend (id, message);
-    }
-}
-
 /*
  * iocLogPrefix()
  */
diff --git a/modules/libcom/src/log/logClient.h b/modules/libcom/src/log/logClient.h
index 1797bbb20..3b3f63add 100644
--- a/modules/libcom/src/log/logClient.h
+++ b/modules/libcom/src/log/logClient.h
@@ -38,7 +38,6 @@ epicsShareFunc void epicsShareAPI iocLogPrefix(const char* prefix);
 /* deprecated interface; retained for backward compatibility */
 /* note: implementations are in iocLog.c, not logClient.c */
 epicsShareFunc logClientId epicsShareAPI logClientInit (void);
-epicsShareFunc void logClientSendMessage (logClientId id, const char *message);
 
 #ifdef __cplusplus
 }

From e28bb3b0e20fe0c18db5c7b9e36da19e95877dcd Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Thu, 19 Sep 2019 10:48:14 +0200
Subject: [PATCH 17/23] epicsSockCountUnsentBytes renamed to
 epicsSocketCountUnsentBytes

---
 modules/libcom/src/log/logClient.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index cd832b60c..28b933e02 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -196,14 +196,14 @@ static void sendMessageChunk(logClient * pClient, const char * message) {
 }
 
 /*
- * epicsSockCountUnsentBytes ()
+ * epicsSocketCountUnsentBytes ()
  * Should go to osd socket support
  */
 #if defined (_WIN32) && WINVER >= _WIN32_WINNT_WIN10
 #include <mstcpip.h>
 #endif
 
-static int epicsSockCountUnsentBytes(SOCKET sock) {
+static int epicsSocketCountUnsentBytes(SOCKET sock) {
 #if defined (_WIN32) && WINVER >= _WIN32_WINNT_WIN10
 /* Windows 10 Version 1703 / Server 2016 */
 /* https://docs.microsoft.com/en-us/windows/win32/api/mstcpip/ns-mstcpip-tcp_info_v0 */
@@ -292,7 +292,7 @@ void epicsShareAPI logClientFlush ( logClientId id )
         logClientClose ( pClient );
     }
     else if ( nSent > 0 && pClient->nextMsgIndex > 0 ) {
-        pClient->backlog = epicsSockCountUnsentBytes ( pClient->sock );
+        pClient->backlog = epicsSocketCountUnsentBytes ( pClient->sock );
         nSent -= pClient->backlog;
         if ( nSent > 0 ) {
             memmove ( pClient->msgBuf, & pClient->msgBuf[nSent],

From 752ec12261cf10155754534c3de8ea7bdfda5e54 Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Thu, 19 Sep 2019 11:42:04 +0200
Subject: [PATCH 18/23] bugfix: memmove'ed to much

---
 modules/libcom/src/log/logClient.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 28b933e02..4e647bd83 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -294,10 +294,10 @@ void epicsShareAPI logClientFlush ( logClientId id )
     else if ( nSent > 0 && pClient->nextMsgIndex > 0 ) {
         pClient->backlog = epicsSocketCountUnsentBytes ( pClient->sock );
         nSent -= pClient->backlog;
-        if ( nSent > 0 ) {
+        pClient->nextMsgIndex -= nSent;
+        if ( nSent > 0 && pClient->nextMsgIndex > 0 ) {
             memmove ( pClient->msgBuf, & pClient->msgBuf[nSent],
                 pClient->nextMsgIndex );
-            pClient->nextMsgIndex -= nSent;
         }
     }
     epicsMutexUnlock ( pClient->mutex );

From 1718647121799f44d0a2c9a624635d2d8f2077fa Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Thu, 19 Sep 2019 12:08:45 +0200
Subject: [PATCH 19/23] epicsSocketCountUnsentBytes returns -1 on failure

---
 modules/libcom/src/log/logClient.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 4e647bd83..476634c5f 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -226,7 +226,7 @@ static int epicsSocketCountUnsentBytes(SOCKET sock) {
     if (ioctl(sock, TIOCOUTQ, &unsent) == 0)
         return unsent;
 #endif
-    return 0;
+    return -1;
 }
 
 /* 
@@ -292,8 +292,11 @@ void epicsShareAPI logClientFlush ( logClientId id )
         logClientClose ( pClient );
     }
     else if ( nSent > 0 && pClient->nextMsgIndex > 0 ) {
-        pClient->backlog = epicsSocketCountUnsentBytes ( pClient->sock );
-        nSent -= pClient->backlog;
+        int backlog = epicsSocketCountUnsentBytes ( pClient->sock );
+        if (backlog >= 0) {
+            pClient->backlog = backlog;
+            nSent -= backlog;
+        }
         pClient->nextMsgIndex -= nSent;
         if ( nSent > 0 && pClient->nextMsgIndex > 0 ) {
             memmove ( pClient->msgBuf, & pClient->msgBuf[nSent],

From cf121f1c14a96b9a3171e5fd46d991cbffa7386b Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Mon, 23 Sep 2019 10:54:17 +0200
Subject: [PATCH 20/23] fix bug from commit f85454. Apparently
 epicsExportSharedSymbols is needed even though epicsExport.h is included

---
 modules/libcom/src/log/logClient.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 476634c5f..ee92c27c4 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -21,6 +21,7 @@
 #include <string.h>
 #include <stdio.h>
 
+#define epicsExportSharedSymbols
 #include "dbDefs.h"
 #include "epicsEvent.h"
 #include "iocLog.h"

From 46912d55166f1664c947e14e3efdd71f6058880e Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Mon, 23 Sep 2019 11:10:32 +0200
Subject: [PATCH 21/23] renamed epicsSocketCountUnsentBytes to
 epicsSocketUnsentCount and moved it to osi/os/

---
 modules/libcom/src/log/logClient.c            | 36 +------------------
 modules/libcom/src/osi/Makefile               |  1 +
 .../src/osi/os/Darwin/osdSockUnsentCount.c    | 17 +++++++++
 .../src/osi/os/Linux/osdSockUnsentCount.c     | 18 ++++++++++
 .../src/osi/os/WIN32/osdSockUnsentCount.c     | 25 +++++++++++++
 .../src/osi/os/default/osdSockUnsentCount.c   | 14 ++++++++
 .../src/osi/os/iOS/osdSockUnsentCount.c       | 17 +++++++++
 modules/libcom/src/osi/osiSock.h              |  6 ++++
 8 files changed, 99 insertions(+), 35 deletions(-)
 create mode 100644 modules/libcom/src/osi/os/Darwin/osdSockUnsentCount.c
 create mode 100644 modules/libcom/src/osi/os/Linux/osdSockUnsentCount.c
 create mode 100644 modules/libcom/src/osi/os/WIN32/osdSockUnsentCount.c
 create mode 100644 modules/libcom/src/osi/os/default/osdSockUnsentCount.c
 create mode 100644 modules/libcom/src/osi/os/iOS/osdSockUnsentCount.c

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index ee92c27c4..73664ff76 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -196,40 +196,6 @@ static void sendMessageChunk(logClient * pClient, const char * message) {
     }
 }
 
-/*
- * epicsSocketCountUnsentBytes ()
- * Should go to osd socket support
- */
-#if defined (_WIN32) && WINVER >= _WIN32_WINNT_WIN10
-#include <mstcpip.h>
-#endif
-
-static int epicsSocketCountUnsentBytes(SOCKET sock) {
-#if defined (_WIN32) && WINVER >= _WIN32_WINNT_WIN10
-/* Windows 10 Version 1703 / Server 2016 */
-/* https://docs.microsoft.com/en-us/windows/win32/api/mstcpip/ns-mstcpip-tcp_info_v0 */
-    DWORD infoVersion = 0, bytesReturned;
-    TCP_INFO_v0 tcpInfo;
-    int status;
-    if ((status = WSAIoctl(sock, SIO_TCP_INFO, &infoVersion, sizeof(infoVersion),
-        &tcpInfo, sizeof(tcpInfo), &bytesReturned, NULL, NULL)) == 0)
-        return tcpInfo.BytesInFlight;
-#elif defined (SO_NWRITE)
-/* macOS / iOS */
-/* https://www.unix.com/man-page/osx/2/setsockopt/ */
-    int unsent;
-    if (getsockopt(sock, SOL_SOCKET, SO_NWRITE, &unsent) == 0)
-        return unsent;
-#elif defined (TIOCOUTQ)
-/* Linux */
-/* https://linux.die.net/man/7/tcp */
-    int unsent;
-    if (ioctl(sock, TIOCOUTQ, &unsent) == 0)
-        return unsent;
-#endif
-    return -1;
-}
-
 /* 
  * logClientSend ()
  */
@@ -293,7 +259,7 @@ void epicsShareAPI logClientFlush ( logClientId id )
         logClientClose ( pClient );
     }
     else if ( nSent > 0 && pClient->nextMsgIndex > 0 ) {
-        int backlog = epicsSocketCountUnsentBytes ( pClient->sock );
+        int backlog = epicsSocketUnsentCount ( pClient->sock );
         if (backlog >= 0) {
             pClient->backlog = backlog;
             nSent -= backlog;
diff --git a/modules/libcom/src/osi/Makefile b/modules/libcom/src/osi/Makefile
index ecbf4c23b..71d8c3d73 100644
--- a/modules/libcom/src/osi/Makefile
+++ b/modules/libcom/src/osi/Makefile
@@ -86,6 +86,7 @@ endif
 
 Com_SRCS += osdSock.c
 Com_SRCS += osdSockAddrReuse.cpp
+Com_SRCS += osdSockUnsentCount.c
 Com_SRCS += osiSock.c
 Com_SRCS += systemCallIntMech.cpp
 Com_SRCS += epicsSocketConvertErrnoToString.cpp
diff --git a/modules/libcom/src/osi/os/Darwin/osdSockUnsentCount.c b/modules/libcom/src/osi/os/Darwin/osdSockUnsentCount.c
new file mode 100644
index 000000000..00ef550bd
--- /dev/null
+++ b/modules/libcom/src/osi/os/Darwin/osdSockUnsentCount.c
@@ -0,0 +1,17 @@
+/*************************************************************************\
+* EPICS BASE is distributed subject to a Software License Agreement found
+* in file LICENSE that is included with this distribution.
+\*************************************************************************/
+
+#include "osiSock.h"
+
+/*
+ * epicsSocketUnsentCount ()
+ * See https://www.unix.com/man-page/osx/2/setsockopt
+ */
+int epicsSocketUnsentCount(SOCKET sock) {
+    int unsent;
+    if (getsockopt(sock, SOL_SOCKET, SO_NWRITE, &unsent) == 0)
+        return unsent;
+    return -1;
+}
diff --git a/modules/libcom/src/osi/os/Linux/osdSockUnsentCount.c b/modules/libcom/src/osi/os/Linux/osdSockUnsentCount.c
new file mode 100644
index 000000000..6f6cbf0fe
--- /dev/null
+++ b/modules/libcom/src/osi/os/Linux/osdSockUnsentCount.c
@@ -0,0 +1,18 @@
+/*************************************************************************\
+* EPICS BASE is distributed subject to a Software License Agreement found
+* in file LICENSE that is included with this distribution.
+\*************************************************************************/
+
+#include <linux/sockios.h>
+#include "osiSock.h"
+
+/*
+ * epicsSocketUnsentCount ()
+ * See https://linux.die.net/man/7/tcp
+ */
+int epicsSocketUnsentCount(SOCKET sock) {
+    int unsent;
+    if (ioctl(sock, SIOCOUTQ, &unsent) == 0)
+        return unsent;
+    return -1;
+}
diff --git a/modules/libcom/src/osi/os/WIN32/osdSockUnsentCount.c b/modules/libcom/src/osi/os/WIN32/osdSockUnsentCount.c
new file mode 100644
index 000000000..c2045bc79
--- /dev/null
+++ b/modules/libcom/src/osi/os/WIN32/osdSockUnsentCount.c
@@ -0,0 +1,25 @@
+/*************************************************************************\
+* EPICS BASE is distributed subject to a Software License Agreement found
+* in file LICENSE that is included with this distribution.
+\*************************************************************************/
+
+#define epicsExportSharedSymbols
+#include "osiSock.h"
+#include <mstcpip.h>
+
+/*
+ * epicsSocketUnsentCount ()
+ * See https://docs.microsoft.com/en-us/windows/win32/api/mstcpip/ns-mstcpip-tcp_info_v0
+ */
+int epicsSocketUnsentCount(SOCKET sock) {
+#if defined (_WIN32) && WINVER >= _WIN32_WINNT_WIN10
+/* Windows 10 Version 1703 / Server 2016 */
+    DWORD infoVersion = 0, bytesReturned;
+    TCP_INFO_v0 tcpInfo;
+    int status;
+    if ((status = WSAIoctl(sock, SIO_TCP_INFO, &infoVersion, sizeof(infoVersion),
+        &tcpInfo, sizeof(tcpInfo), &bytesReturned, NULL, NULL)) == 0)
+        return tcpInfo.BytesInFlight;
+#endif
+    return -1;
+}
diff --git a/modules/libcom/src/osi/os/default/osdSockUnsentCount.c b/modules/libcom/src/osi/os/default/osdSockUnsentCount.c
new file mode 100644
index 000000000..61094c710
--- /dev/null
+++ b/modules/libcom/src/osi/os/default/osdSockUnsentCount.c
@@ -0,0 +1,14 @@
+/*************************************************************************\
+* EPICS BASE is distributed subject to a Software License Agreement found
+* in file LICENSE that is included with this distribution.
+\*************************************************************************/
+
+#include "osiSock.h"
+
+/*
+ * epicsSocketUnsentCount ()
+ */
+int epicsSocketUnsentCount(SOCKET sock) {
+    /* not implemented */
+    return -1;
+}
diff --git a/modules/libcom/src/osi/os/iOS/osdSockUnsentCount.c b/modules/libcom/src/osi/os/iOS/osdSockUnsentCount.c
new file mode 100644
index 000000000..00ef550bd
--- /dev/null
+++ b/modules/libcom/src/osi/os/iOS/osdSockUnsentCount.c
@@ -0,0 +1,17 @@
+/*************************************************************************\
+* EPICS BASE is distributed subject to a Software License Agreement found
+* in file LICENSE that is included with this distribution.
+\*************************************************************************/
+
+#include "osiSock.h"
+
+/*
+ * epicsSocketUnsentCount ()
+ * See https://www.unix.com/man-page/osx/2/setsockopt
+ */
+int epicsSocketUnsentCount(SOCKET sock) {
+    int unsent;
+    if (getsockopt(sock, SOL_SOCKET, SO_NWRITE, &unsent) == 0)
+        return unsent;
+    return -1;
+}
diff --git a/modules/libcom/src/osi/osiSock.h b/modules/libcom/src/osi/osiSock.h
index 061619e89..e1c2de881 100644
--- a/modules/libcom/src/osi/osiSock.h
+++ b/modules/libcom/src/osi/osiSock.h
@@ -52,6 +52,12 @@ enum epicsSocketSystemCallInterruptMechanismQueryInfo {
 epicsShareFunc enum epicsSocketSystemCallInterruptMechanismQueryInfo 
         epicsSocketSystemCallInterruptMechanismQuery ();
 
+/*
+ * Some systems (e.g Linux and Windows 10) allow to check the amount
+ * of unsent data in the output queue.
+ * Returns -1 if the information is not available.
+ */
+epicsShareFunc int epicsSocketUnsentCount(SOCKET sock);
 
 /*
  * convert socket address to ASCII in this order

From 4bb81654d60a5d343aeee1aa1ac8276c9ab43f75 Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Fri, 4 Oct 2019 14:32:07 +0200
Subject: [PATCH 22/23] use EPICS_PRIVATE_API macro and fix bug with darwin/ios

---
 modules/libcom/src/log/logClient.c                     | 1 +
 modules/libcom/src/osi/os/Darwin/osdSockUnsentCount.c  | 4 +++-
 modules/libcom/src/osi/os/Linux/osdSockUnsentCount.c   | 1 +
 modules/libcom/src/osi/os/WIN32/osdSockUnsentCount.c   | 1 +
 modules/libcom/src/osi/os/default/osdSockUnsentCount.c | 1 +
 modules/libcom/src/osi/os/iOS/osdSockUnsentCount.c     | 4 +++-
 modules/libcom/src/osi/osiSock.h                       | 2 ++
 7 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/modules/libcom/src/log/logClient.c b/modules/libcom/src/log/logClient.c
index 73664ff76..9a09ef7b7 100644
--- a/modules/libcom/src/log/logClient.c
+++ b/modules/libcom/src/log/logClient.c
@@ -21,6 +21,7 @@
 #include <string.h>
 #include <stdio.h>
 
+#define EPICS_PRIVATE_API
 #define epicsExportSharedSymbols
 #include "dbDefs.h"
 #include "epicsEvent.h"
diff --git a/modules/libcom/src/osi/os/Darwin/osdSockUnsentCount.c b/modules/libcom/src/osi/os/Darwin/osdSockUnsentCount.c
index 00ef550bd..20bd82b14 100644
--- a/modules/libcom/src/osi/os/Darwin/osdSockUnsentCount.c
+++ b/modules/libcom/src/osi/os/Darwin/osdSockUnsentCount.c
@@ -3,6 +3,7 @@
 * in file LICENSE that is included with this distribution.
 \*************************************************************************/
 
+#define EPICS_PRIVATE_API
 #include "osiSock.h"
 
 /*
@@ -11,7 +12,8 @@
  */
 int epicsSocketUnsentCount(SOCKET sock) {
     int unsent;
-    if (getsockopt(sock, SOL_SOCKET, SO_NWRITE, &unsent) == 0)
+    socklen_t len = sizeof(unsent);
+    if (getsockopt(sock, SOL_SOCKET, SO_NWRITE, &unsent, &len) == 0)
         return unsent;
     return -1;
 }
diff --git a/modules/libcom/src/osi/os/Linux/osdSockUnsentCount.c b/modules/libcom/src/osi/os/Linux/osdSockUnsentCount.c
index 6f6cbf0fe..3c0a8f915 100644
--- a/modules/libcom/src/osi/os/Linux/osdSockUnsentCount.c
+++ b/modules/libcom/src/osi/os/Linux/osdSockUnsentCount.c
@@ -4,6 +4,7 @@
 \*************************************************************************/
 
 #include <linux/sockios.h>
+#define EPICS_PRIVATE_API
 #include "osiSock.h"
 
 /*
diff --git a/modules/libcom/src/osi/os/WIN32/osdSockUnsentCount.c b/modules/libcom/src/osi/os/WIN32/osdSockUnsentCount.c
index c2045bc79..fe68ead01 100644
--- a/modules/libcom/src/osi/os/WIN32/osdSockUnsentCount.c
+++ b/modules/libcom/src/osi/os/WIN32/osdSockUnsentCount.c
@@ -4,6 +4,7 @@
 \*************************************************************************/
 
 #define epicsExportSharedSymbols
+#define EPICS_PRIVATE_API
 #include "osiSock.h"
 #include <mstcpip.h>
 
diff --git a/modules/libcom/src/osi/os/default/osdSockUnsentCount.c b/modules/libcom/src/osi/os/default/osdSockUnsentCount.c
index 61094c710..ef01e9b24 100644
--- a/modules/libcom/src/osi/os/default/osdSockUnsentCount.c
+++ b/modules/libcom/src/osi/os/default/osdSockUnsentCount.c
@@ -3,6 +3,7 @@
 * in file LICENSE that is included with this distribution.
 \*************************************************************************/
 
+#define EPICS_PRIVATE_API
 #include "osiSock.h"
 
 /*
diff --git a/modules/libcom/src/osi/os/iOS/osdSockUnsentCount.c b/modules/libcom/src/osi/os/iOS/osdSockUnsentCount.c
index 00ef550bd..20bd82b14 100644
--- a/modules/libcom/src/osi/os/iOS/osdSockUnsentCount.c
+++ b/modules/libcom/src/osi/os/iOS/osdSockUnsentCount.c
@@ -3,6 +3,7 @@
 * in file LICENSE that is included with this distribution.
 \*************************************************************************/
 
+#define EPICS_PRIVATE_API
 #include "osiSock.h"
 
 /*
@@ -11,7 +12,8 @@
  */
 int epicsSocketUnsentCount(SOCKET sock) {
     int unsent;
-    if (getsockopt(sock, SOL_SOCKET, SO_NWRITE, &unsent) == 0)
+    socklen_t len = sizeof(unsent);
+    if (getsockopt(sock, SOL_SOCKET, SO_NWRITE, &unsent, &len) == 0)
         return unsent;
     return -1;
 }
diff --git a/modules/libcom/src/osi/osiSock.h b/modules/libcom/src/osi/osiSock.h
index e1c2de881..6e3b053c5 100644
--- a/modules/libcom/src/osi/osiSock.h
+++ b/modules/libcom/src/osi/osiSock.h
@@ -52,12 +52,14 @@ enum epicsSocketSystemCallInterruptMechanismQueryInfo {
 epicsShareFunc enum epicsSocketSystemCallInterruptMechanismQueryInfo 
         epicsSocketSystemCallInterruptMechanismQuery ();
 
+#ifdef EPICS_PRIVATE_API
 /*
  * Some systems (e.g Linux and Windows 10) allow to check the amount
  * of unsent data in the output queue.
  * Returns -1 if the information is not available.
  */
 epicsShareFunc int epicsSocketUnsentCount(SOCKET sock);
+#endif
 
 /*
  * convert socket address to ASCII in this order

From 5e6226e595975753f3f7a256982c0d77f6643394 Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@gmail.com>
Date: Thu, 24 Oct 2019 19:15:31 -0700
Subject: [PATCH 23/23] osdSockUnsentCount.c check for existance of
 SIO_TCP_INFO

---
 modules/libcom/src/osi/os/WIN32/osdSockUnsentCount.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/libcom/src/osi/os/WIN32/osdSockUnsentCount.c b/modules/libcom/src/osi/os/WIN32/osdSockUnsentCount.c
index fe68ead01..3f4ab3eee 100644
--- a/modules/libcom/src/osi/os/WIN32/osdSockUnsentCount.c
+++ b/modules/libcom/src/osi/os/WIN32/osdSockUnsentCount.c
@@ -13,7 +13,7 @@
  * See https://docs.microsoft.com/en-us/windows/win32/api/mstcpip/ns-mstcpip-tcp_info_v0
  */
 int epicsSocketUnsentCount(SOCKET sock) {
-#if defined (_WIN32) && WINVER >= _WIN32_WINNT_WIN10
+#ifdef SIO_TCP_INFO
 /* Windows 10 Version 1703 / Server 2016 */
     DWORD infoVersion = 0, bytesReturned;
     TCP_INFO_v0 tcpInfo;