More detailed description for building on Windows

src/win32/README.md

@@ -1,41 +1,81 @@
 # Instructions to compile on Windows
+To use this library on Windows, we have to generate `.dll` file out of this code. On successful build we will get a set of 3 files :
+- modbus.dll
+- libmodbus.a
+- libmodbus.def
 
-## Create a new Visual Studio project with the library included
+You use `libmodbus.a` when you write your code and compile. While running your executable you use `modbus.dll` either by copying it in the same folder where executable is or by adding `path-to-modbus.dll` in the `ENVIRONMENT VARIABLES - PATH` of Windows.
 
-Download the latest version of libmodbus source code from Github
+
+Currently, to compile and build this code you have 3 major options.
+
+1. You can use `Visual Studio` and create a project from `modbus.vcproject` in `src/win32` folder
+2. Use some other IDE and import this as a `Visual Studio Project` in that IDE
+3. Create a `dll project` in any IDE and build the code from scratch (this option comes if import is not available or successful) 
+
+
+## First do this
+
+In all three cases you have to do the following steps :
+
+- Download the latest version of libmodbus source code from Github
 `https://github.com/stephane/libmodbus` -> Code -> Download ZIP.
 
-Once the archive is decompressed, launch a Windows terminal (`cmd`) in
+- Once the archive is decompressed, launch a Windows terminal (`cmd`) in
 `src/win32` directory and run `cscript configure.js`.
 
-1. copy the file `config.h` from `src/win32` to `src`.
-2. create a new 'Console App' project under Visual Studio.
-3. create a new directory called `libmodbus` inside your VS project (same level
+- Copy the generated file `config.h` from `src/win32` to `src`.
+
+- Proceed with one of the 3 options below
+
+
+## Option 1: Create a new Visual Studio project with the library included
+
+1. create a new 'Console App' project under Visual Studio.
+2. create a new directory called `libmodbus` inside your VS project (same level
    as the `.vcxproj` file).
-4. copy all `*.c` and `*.h` from libmodbus `src` in the new `libmodbus` folder
+3. copy all `*.c` and `*.h` from libmodbus `src` in the new `libmodbus` folder
    of your VS project.
-5. copy `modbus.rc` in your VS project (same level as the `.vcxproj` file).
-6. drag and drop `libmodbus/*.c` files (4) in *Solution Explorer -> Source Files*.
-7. drag and drop `libmodbus/*.h` files (8) in *Solution Explorer -> Header Files*.
-8. drag and drop `modbus.rc` file in *Solution Explorer -> Resource Files*.
-9. check path is `#include "modbus-version.h"` in `modbus.rc`.
-10. in the **Property Pages** of the project *Configuration Properties -> C/C++
+4. copy `modbus.rc` in your VS project (same level as the `.vcxproj` file).
+5. drag and drop `libmodbus/*.c` files (4) in *Solution Explorer -> Source Files*.
+6. drag and drop `libmodbus/*.h` files (8) in *Solution Explorer -> Header Files*.
+7. drag and drop `modbus.rc` file in *Solution Explorer -> Resource Files*.
+8. check path is `#include "modbus-version.h"` in `modbus.rc`.
+9. in the **Property Pages** of the project *Configuration Properties -> C/C++
     -> General -> Additional Include Directories*, add `libmodbus` folder.
-11. in the **Property Pages** of the project *Configuration Properties ->
+10. in the **Property Pages** of the project *Configuration Properties ->
     Resources -> Additional Include Directories*, add `libmodbus` folder.
-12. in the **Property Pages** of the project *Configuration Properties -> Linker
+11. in the **Property Pages** of the project *Configuration Properties -> Linker
     -> Input*, define `ws2_32.lib`.
-13. if required, add `_CRT_SECURE_NO_WARNINGS` to *C/C++ -> Preprocessor ->
+12. if required, add `_CRT_SECURE_NO_WARNINGS` to *C/C++ -> Preprocessor ->
     Preprocessor Definitions*.
 
-## Create a libmodbus DLL
 
-This directory contains the project file for Visual Studio to build `modbus.dll`
-and import library `modbus.lib`.
+## Option 2: Import as Visual Studio project in any other IDE
+
+After you have generated `config.h` file using cscript and moved it to `src` folder, check in your IDE if there is an option to `import Visual Studio project` (CodeBlocks has it).
+
+1. Select `modbus.vcproject` as file to import from (this file is in `src/win32` folder). You might get some errors while importing but check the severity of the error before proceeding.
+2. Build the project and you will get set of 3 files in `src/win32`(`modbus.dll`, `libmodbus.a`, `libmodbus.def`).
+
+
+## Option 3: Build the library as DLL project
+
+After you have generated `config.h` file using `cscript` and copied it to `src` folder,
+
+1. Create a new project as DLL (Dynamic Link Library) and select `src` as the project directory
+2. Delete generated `.c` `.cpp` and `.h` files (Codeblocks generated `main.cpp` and `main.h` which have to be deleted).
+3. Add all the .c and .h files of libmodbus to this project as source and header files.
+4. Add `src` as the `include directory` of the project (we still don't have separate `include directory`). 
+5. Add `ws2_32` library to the linker library
+6. On successful build, set of 3 files (`modbus.dll`, `libmodbus.a`, `libmodbus.def`) will be generated in `bin/Debug` or somewhere similar.
 
-In the Windows terminal, run `cscript configure.js` to generate:
 
-- `config.h`
-- `modbus-version.h` are generated using configure.js.
+# Using generated library
 
-To write...
+1. To use the generated library create a separate `Console project`.
+2. Add the `src` folder of libmodbus library as the `Include directory` for your project or use the `libmodbus` directory that has all the header files.
+3. Link `libmodbus.a` in linker setting before generating the `.exe` file for your project.
+4. Build the project to generate an `.exe` file for this project.
+5. For running the `.exe` file of your test project, place the `modbus.dll` in the same folder as the `.exe` file. Or, alternatively add the path to `modbus.dll` in the `ENVIRONMENT VARIABLES - PATH` in Windows.
+6. Run your `.exe` file