--- src\libs\zbxcomms\comms.c.orig	2019-10-14 22:42:50 +0500
+++ src\libs\zbxcomms\comms.c	2019-10-14 22:46:25 +0500
@@ -1627,7 +1627,7 @@
 		}
 		else
 		{
-			if (0 != (left = MIN(ZBX_TCP_LINE_LEN - s->read_bytes, (size_t)(ptr - buffer))))
+			if (ptr && (left = MIN(ZBX_TCP_LINE_LEN - s->read_bytes, (size_t)(ptr - buffer))))
 			{
 				/* fill the string to the defined limit */
 				zbx_strncpy_alloc(&s->buffer, &alloc, &offset, buffer, left);
@@ -1635,7 +1635,7 @@
 			}
 
 			/* if the line exceeds the defined limit then truncate it by skipping data until the newline */
-			if (NULL != ptr)
+			if (ptr)
 			{
 				zbx_strncpy_alloc(&s->buffer, &alloc, &offset, ptr, nbytes - (ptr - buffer));
 				s->read_bytes += nbytes - (ptr - buffer);