From 8d8bb4fdf0338ddde196f74fdf557f221ecdcb52 Mon Sep 17 00:00:00 2001
From: Cedric Boudinet <boudinpg@gmail.com>
Date: Thu, 10 Nov 2022 15:50:56 +0100
Subject: [PATCH 1/3] adding get_query_function

---
 src/modbus.c | 10 ++++++++++
 src/modbus.h |  1 +
 2 files changed, 11 insertions(+)

diff --git a/src/modbus.c b/src/modbus.c
index e7379d371..42804a6d2 100644
--- a/src/modbus.c
+++ b/src/modbus.c
@@ -1856,6 +1856,16 @@ int modbus_get_header_length(modbus_t *ctx)
     return ctx->backend->header_length;
 }
 
+int modbus_get_query_function(modbus_t *ctx, const uint8_t * req)
+{
+    if (ctx == NULL) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    return req[ctx->backend->header_length];
+}
+
 int modbus_enable_quirks(modbus_t *ctx, uint32_t quirks_mask)
 {
     if (ctx == NULL) {
diff --git a/src/modbus.h b/src/modbus.h
index 55ef08a0d..3d0fdcfb7 100644
--- a/src/modbus.h
+++ b/src/modbus.h
@@ -206,6 +206,7 @@ MODBUS_API int
 modbus_set_indication_timeout(modbus_t *ctx, uint32_t to_sec, uint32_t to_usec);
 
 MODBUS_API int modbus_get_header_length(modbus_t *ctx);
+int modbus_get_query_function(modbus_t *ctx, const uint8_t * req);
 
 MODBUS_API int modbus_connect(modbus_t *ctx);
 MODBUS_API void modbus_close(modbus_t *ctx);

From 39d3a97f5c61649edf4008c3fae7771ef15a6b70 Mon Sep 17 00:00:00 2001
From: Cedric Boudinet <boudinpg@gmail.com>
Date: Tue, 15 Nov 2022 21:38:18 +0100
Subject: [PATCH 2/3] updating docs

---
 docs/index.md                     |  4 ++++
 docs/modbus_get_query_function.md | 20 ++++++++++++++++++++
 src/modbus.c                      |  4 ++--
 3 files changed, 26 insertions(+), 2 deletions(-)
 create mode 100644 docs/modbus_get_query_function.md

diff --git a/docs/index.md b/docs/index.md
index cefa9ce51..a6a31efce 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -205,6 +205,10 @@ Information about header:
 
 - [modbus_get_header_length](modbus_get_header_length.md)
 
+Information about query:
+
+- [modbus_get_query_function](modbus_get_query_function.md)
+
 ## Data handling
 
 Macros for data manipulation:
diff --git a/docs/modbus_get_query_function.md b/docs/modbus_get_query_function.md
new file mode 100644
index 000000000..418dbea65
--- /dev/null
+++ b/docs/modbus_get_query_function.md
@@ -0,0 +1,20 @@
+# modbus_get_header_length
+
+## Name
+
+modbus_get_query_function- retrieve the function code of a query
+
+## Synopsis
+
+```c
+int modbus_get_header_length(modbus_t *ctx, const uint8_t * query);
+```
+
+## Description
+
+The *modbus_get_query_function()* function shall retrieve the function code
+of a query. It can be useful for modbus server development.
+
+## Return value
+
+The function code a the query.
diff --git a/src/modbus.c b/src/modbus.c
index 42804a6d2..5d2a1988a 100644
--- a/src/modbus.c
+++ b/src/modbus.c
@@ -1856,14 +1856,14 @@ int modbus_get_header_length(modbus_t *ctx)
     return ctx->backend->header_length;
 }
 
-int modbus_get_query_function(modbus_t *ctx, const uint8_t * req)
+int modbus_get_query_function(modbus_t *ctx, const uint8_t * query)
 {
     if (ctx == NULL) {
         errno = EINVAL;
         return -1;
     }
 
-    return req[ctx->backend->header_length];
+    return query[ctx->backend->header_length];
 }
 
 int modbus_enable_quirks(modbus_t *ctx, uint32_t quirks_mask)

From 32c311b82ccd73f008cce71bfb7040764e1d2c62 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Boudinet?= <boudinpg@gmail.com>
Date: Tue, 15 Nov 2022 21:41:43 +0100
Subject: [PATCH 3/3] Update modbus_get_query_function.md

---
 docs/modbus_get_query_function.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/docs/modbus_get_query_function.md b/docs/modbus_get_query_function.md
index 418dbea65..02e959fdf 100644
--- a/docs/modbus_get_query_function.md
+++ b/docs/modbus_get_query_function.md
@@ -1,4 +1,4 @@
-# modbus_get_header_length
+# modbus_get_query_function
 
 ## Name
 
@@ -7,7 +7,7 @@ modbus_get_query_function- retrieve the function code of a query
 ## Synopsis
 
 ```c
-int modbus_get_header_length(modbus_t *ctx, const uint8_t * query);
+int modbus_get_query_function(modbus_t *ctx, const uint8_t * query);
 ```
 
 ## Description
@@ -17,4 +17,4 @@ of a query. It can be useful for modbus server development.
 
 ## Return value
 
-The function code a the query.
+The function code of the query.