You are compiling main.c, which is a C source file. You should rename this to main.cpp (and update your CMakeLists.txt or Makefiles accordingly) to have the tools recognize this as a C++ source file and compile it using the C++ compiler. BTW, it's a lot easier to read the error messages if you cut a...

Parallel loops are indeed possible, but it's done through FreeRTOS constructs instead of being built in to C. You can start up multiple tasks, each of which is running their own main processing loop. If you have one for each of the two devices you're managing, you can take the results from each of t...

What do you expect to happen with this bit of HTML? I'm not sure what you mean, since I don't normally think of "running HTML". You can parse it and display something on a user interface (such as within a web browser). So if you're asking how to present a slider to a user from your ESP32 code, there...

The code running on the ESP32 is more like the kernel than an Unix-like process. There are no processes, just tasks within a single address space. So I'm not in any way surprised that popen isn't part of the available libraries. Also, note that popen isn't part of ANSI C (it's probably standardized ...

examples/protocols/sockets/tcp_client in esp-idf v4.1 contains basic socket example code, using IDF only (not the Arduino wrappers). The sockets interface for TCP code works pretty much just like the sockets interface anywhere else, so books or websites that cover Unix network programming will be sp...

You certainly CAN use the Huzzah32 as a platform for native ESP-IDF programs. You have to pay attention to I/O pin definitions, since you don't have a definition for them within the IDF itself. You can grab them from the Arduino code, or just use the pinout diagrams from the Adafruit site (https://l...

<string.h> is the C library header file for functions like strcmp.

<string> is the C++ library header file which contains the std::string class declaration.

You need to change <string.h> to <string>.