From 70a2e6e624ae7785c0e5eeb8f5caecfc0ee157c8 Mon Sep 17 00:00:00 2001
From: Stéphane Raimbault <stephane.raimbault@gmail.com>
Date: Tue, 10 Aug 2010 08:59:11 +0200
Subject: [PATCH] Test return code of receive_msg_req to have an explicit error path

---
 src/modbus.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/modbus.c b/src/modbus.c
index d12e3df..4d9a2fc 100644
--- a/src/modbus.c
+++ b/src/modbus.c
@@ -1295,10 +1295,12 @@ static int read_registers(modbus_t *ctx, int function, int addr, int nb,
         int i;
 
         rc = receive_msg_req(ctx, req, rsp);
+        if (rc == -1) {
+            return -1;
+        }
 
         offset = TAB_HEADER_LENGTH[ctx->type_com];
 
-        /* If rc is negative, the loop is jumped ! */
         for (i = 0; i < rc; i++) {
             /* shift reg hi_byte to temp OR with lo_byte */
             data_dest[i] = (rsp[offset + 2 + (i << 1)] << 8) |
--
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