Block attempts to put more bytes than will fit.

documentation/RELEASE_NOTES.html

@@ -12,6 +12,11 @@
 <h2 align="center">Changes between 3.14.10 and 3.14.11</h2>
 <!-- Insert new items below here ... -->
 
+<h4>epicsRingBytes</h4>
+
+<p>Partial puts are not supported.  An attempt to put more bytes than currently free will be rejected.</p>
+
+<h4>camonitor timestamp support</h4>
 <h4>Long string support</h4>
 
 <p>The IOC now provides support for strings longer than 40 characters through

src/libCom/ring/epicsRingBytes.c

@@ -105,7 +105,7 @@ epicsShareFunc int epicsShareAPI epicsRingBytesPut(
     if (nextPut < nextGet) {
         freeCount = nextGet - nextPut - SLOP;
         if (nbytes > freeCount)
-            nbytes = freeCount;
+            return 0;
         if (nbytes)
             memcpy ((void *)&pring->buffer[nextPut], value, nbytes);
         nextPut += nbytes;
@@ -113,7 +113,7 @@ epicsShareFunc int epicsShareAPI epicsRingBytesPut(
     else {
         freeCount = size - nextPut + nextGet - SLOP;
         if (nbytes > freeCount)
-            nbytes = freeCount;
+            return 0;
         topCount = size - nextPut;
         copyCount = (nbytes > topCount) ?  topCount : nbytes;
         if (copyCount)
@@ -134,8 +134,7 @@ epicsShareFunc void epicsShareAPI epicsRingBytesFlush(epicsRingBytesId id)
 {
     ringPvt *pring = (ringPvt *)id;
 
-    pring->nextGet = 0;
-    pring->nextPut = 0;
+    pring->nextGet = pring->nextPut;
 }
 
 epicsShareFunc int epicsShareAPI epicsRingBytesFreeBytes(epicsRingBytesId id)