From c7c7c768a6b60259b9e38df39a8da909b53a8791 Mon Sep 17 00:00:00 2001
From: Stéphane Raimbault <stephane.raimbault@gmail.com>
Date: Tue, 4 Aug 2015 15:30:17 +0200
Subject: [PATCH] Improve new_rtu and set_slave documentation (related to #276)

---
 doc/modbus_new_rtu.txt   | 13 ++++++++++++-
 doc/modbus_set_slave.txt | 26 ++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/doc/modbus_new_rtu.txt b/doc/modbus_new_rtu.txt
index 8cc9cc0..34fc419 100644
--- a/doc/modbus_new_rtu.txt
+++ b/doc/modbus_new_rtu.txt
@@ -15,7 +15,7 @@ SYNOPSIS
 
 DESCRIPTION
 -----------
-The *modbus_new_rtu()* function shall allocate and initialize a modbus_t
+The *modbus_new_rtu()* function shall allocate and initialize a _modbus_t_
 structure to communicate in RTU mode on a serial line.
 
 The _device_ argument specifies the name of the serial port handled by the OS,
@@ -37,6 +37,9 @@ values are 5, 6, 7 and 8.
 The _stop_bits_ argument specifies the bits of stop, the allowed values are 1
 and 2.
 
+Once the _modbus_t_ structure is initialized, you must set the slave of your
+device with linkmb:modbus_set_slave[3] and connect to the serial bus with
+linkmb:modbus_connect[3].
 
 RETURN VALUE
 ------------
@@ -62,6 +65,14 @@ if (ctx == NULL) {
     fprintf(stderr, "Unable to create the libmodbus context\n");
     return -1;
 }
+
+modbus_set_slave(ctx, YOUR_DEVICE_ID);
+
+if (modbus_connect(ctx) == -1) {
+    fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
+    modbus_free(ctx);
+    return -1;
+}
 -------------------
 
 SEE ALSO
diff --git a/doc/modbus_set_slave.txt b/doc/modbus_set_slave.txt
index 7a7ff49..23d786d 100644
--- a/doc/modbus_set_slave.txt
+++ b/doc/modbus_set_slave.txt
@@ -45,6 +45,32 @@ ERRORS
 The slave number is invalid.
 
 
+EXAMPLE
+-------
+[source,c]
+-------------------
+modbus_t *ctx;
+
+ctx = modbus_new_rtu("/dev/ttyUSB0", 115200, 'N', 8, 1);
+if (ctx == NULL) {
+    fprintf(stderr, "Unable to create the libmodbus context\n");
+    return -1;
+}
+
+rc = modbus_set_slave(ctx, YOUR_DEVICE_ID);
+if (rc == -1) {
+    fprintf(stderr, "Invalid slave ID\n");
+    modbus_free(ctx);
+    return -1;
+}
+
+if (modbus_connect(ctx) == -1) {
+    fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
+    modbus_free(ctx);
+    return -1;
+}
+-------------------
+
 AUTHORS
 -------
 The libmodbus documentation was written by Stéphane Raimbault
--
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