CPP Utils

This directory contains a wealth of C++ classes that have been found useful when working in C++ in conjunction with the ESP-IDF. The classes have been documented using doxygen so one can run a doxygen processor over them to create the user guides and programming references.

Compiling the C++ classes

The C++ classes found here exist as an ESP-IDF component. To build the classes and then use them in your project perform the following steps:

1. Create an ESP-IDF project.
2. Create a directory called components in the root of your ESP-IDF project.
3. Copy this directory (cpp_utils) into your new components directory. The result will be <project>/components/cpp_utils/<files>.
4. In your ESP-IDF project build as normal.

The C++ classes will be compiled and available to be used in your own code.

Adding a main function

When working with C++, your calling function should also be written in C++. Consider replacing your main.c with the following main.cpp file:

extern "C" {
   void app_main();
}

void app_main() {
   // Your code goes here
}

The way to read the above is that we are defining a global function called app_main but we are saying that its external linkage (i.e. how it is found and called) is using the C language convention. However, since the source file is main.cpp and hence compiled by the C++ compiler, you can utilize C++ classes and language features within and, since it has C linkage, it will satisfy the ESP-IDF environment as the entry point into your own code.

BLE Functions

The Bluetooth BLE functions are only compiled if Bluetooth is enabled in make menuconfig. This is primarily because the ESP-IDF build system has chosen to only compile the underlying BLE functions if Bluetooth is enabled.

Building the Documentation

The code is commented using the Doxygen tags. As such we can run Doxygen to generate the data. I use doxywizard using the Doxyfile located in this directory.

Building the Arduino libraries

Some of the classes in this package also have applicability in an Arduino environment. A Makefile called Makefile.arduino is provided to build the libraries. For example:

$ make -f Makefile.arduino

The results of this will be ZIP files found in the Arduino directory relative to this one. Targets include:

• build_ble - Build the BLE libraries. See also: Arduino BLE Support .