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Arduino core for the ESP32
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[documentation] where are the thread libs listed (e.g., like WiFi)? #7394

Open dsyleixa opened 1 year ago

dsyleixa commented 1 year ago

Board

ESP32 (all)

Device Description

ESP32 (all)

Hardware Configuration

default

Version

v1.0.x, 2.0.x

IDE Name

Arduino IDE

Operating System

Windows 7/10/11

Flash frequency

any

PSRAM enabled

no

Upload speed

all

Description

[documentation] where are the thread libs listed ? I can't find it in the libraries folders next to FS, i2s, WiFi, SD, Wiire, whatever...

Sketch

any

Debug Message

any

Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

VojtechBartoska commented 1 year ago

so far, we have documented this: https://docs.espressif.com/projects/arduino-esp32/en/latest/libraries.html#apis

dsyleixa commented 1 year ago

hmmh, I don't see anything there which is named "thread" or s.th. (for #include <thread>)

<html><body>
<!--StartFragment--><div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
           <div itemprop="articleBody">

  <div class="section" id="libraries">
<h1>Libraries<a class="headerlink" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/libraries.html#libraries" title="Permalink to this headline">¶</a></h1>
<p>Here is where the Libraries API’s descriptions are located:</p>
<div class="section" id="supported-peripherals">
<h2>Supported Peripherals<a class="headerlink" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/libraries.html#supported-peripherals" title="Permalink to this headline">¶</a></h2>
<p>Currently, the Arduino ESP32 supports the following peripherals with Arduino APIs.</p>
<div class="wy-table-responsive">

Peripheral | ESP32 | ESP32-S2 | ESP32-C3 | Comments
-- | -- | -- | -- | --
ADC | Yes | Yes | Yes |  
Bluetooth | Yes | Not Supported | Not Supported | Bluetooth Classic
BLE | Yes | Not Supported | Yes |  
DAC | Yes | Yes | Not Supported |  
Ethernet | Yes | Not Supported | Not Supported | (*)
GPIO | Yes | Yes | Yes |  
Hall Sensor | Yes | Not Supported | Not Supported |  
I2C | Yes | Yes | Yes |  
I2S | Yes | No | No | WIP
LEDC | Yes | Yes | Yes |  
Motor PWM | No | Not Supported | Not Supported |  
Pulse Counter | No | No | No |  
RMT | Yes | Yes | Yes |  
SDIO | No | No | No |  
SPI | Yes | Yes | Yes |  
Timer | Yes | Yes | Yes |  
Temp. Sensor | Not Supported | Yes | Yes |  
Touch | Yes | Yes | Not Supported |  
TWAI | No | No | No |  
UART | Yes | Yes | Yes |  
USB | Not Supported | Yes | Yes | ESP32-C3 only CDC/JTAG
Wi-Fi | Yes | Yes | Yes |  

</div>
<div class="section" id="notes">
<h3>Notes<a class="headerlink" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/libraries.html#notes" title="Permalink to this headline">¶</a></h3>
<p>(*) SPI Ethernet is supported by all ESP32 families and RMII only for ESP32.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>Some peripherals are not available for all ESP32 families. To see more details about it, see the corresponding SoC at <a class="reference external" href="https://products.espressif.com">Product Selector</a> page.</p>
</div>
</div>
</div>
<div class="section" id="datasheet">
<h2>Datasheet<a class="headerlink" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/libraries.html#datasheet" title="Permalink to this headline">¶</a></h2>
<ul class="simple">
<li><p><a class="reference external" href="https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf">ESP32</a> (Datasheet)</p></li>
<li><p><a class="reference external" href="https://www.espressif.com/sites/default/files/documentation/esp32-s2_datasheet_en.pdf">ESP32-S2</a> (Datasheet)</p></li>
<li><p><a class="reference external" href="https://www.espressif.com/sites/default/files/documentation/esp32-c3_datasheet_en.pdf">ESP32-C3</a> (Datasheet)</p></li>
<li><p><a class="reference external" href="https://www.espressif.com/sites/default/files/documentation/esp32-s3_datasheet_en.pdf">ESP32-S3</a> (Datasheet)</p></li>
</ul>
</div>
<div class="section" id="apis">
<h2>APIs<a class="headerlink" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/libraries.html#apis" title="Permalink to this headline">¶</a></h2>
<p>The Arduino ESP32 offers some unique APIs, described in this section:</p>
<div class="toctree-wrapper compound">
<ul>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/adc.html">ADC</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/bluetooth.html">Bluetooth API</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/dac.html">DAC</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/deepsleep.html">Deep Sleep</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/espnow.html">ESP-NOW</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/gpio.html">GPIO</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/i2c.html">I2C</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/i2s.html">I2S</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/ledc.html">LED Control (LEDC)</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/preferences.html">Preferences</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/rainmaker.html">RainMaker</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/reset_reason.html">Reset Reason</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/sigmadelta.html">SigmaDelta</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/timer.html">Timer</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/usb.html">USB API</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/usb_cdc.html">USB CDC</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/usb_msc.html">USB MSC</a></li>
<li class="toctree-l1"><a class="reference internal" href="https://docs.espressif.com/projects/arduino-esp32/en/latest/api/wifi.html">Wi-Fi API</a></li>
</ul>
</div>
</div>
</div>

           </div>
          </div>
          <footer><div class="rst-footer-buttons" role="navigation" aria-label="Footer">
        </div></footer>

    <!--EndFragment-->
</body>
</html>Libraries[¶](https://docs.espressif.com/projects/arduino-esp32/en/latest/libraries.html#libraries)

Here is where the Libraries API’s descriptions are located:
Supported Peripherals[¶](https://docs.espressif.com/projects/arduino-esp32/en/latest/libraries.html#supported-peripherals)

Currently, the Arduino ESP32 supports the following peripherals with Arduino APIs.

Peripheral

ESP32

ESP32-S2

ESP32-C3

Comments

ADC

Yes

Yes

Yes

Bluetooth

Yes

Not Supported

Not Supported

Bluetooth Classic

BLE

Yes

Not Supported

Yes

DAC

Yes

Yes

Not Supported

Ethernet

Yes

Not Supported

Not Supported

(*)

GPIO

Yes

Yes

Yes

Hall Sensor

Yes

Not Supported

Not Supported

I2C

Yes

Yes

Yes

I2S

Yes

No

No

WIP

LEDC

Yes

Yes

Yes

Motor PWM

No

Not Supported

Not Supported

Pulse Counter

No

No

No

RMT

Yes

Yes

Yes

SDIO

No

No

No

SPI

Yes

Yes

Yes

Timer

Yes

Yes

Yes

Temp. Sensor

Not Supported

Yes

Yes

Touch

Yes

Yes

Not Supported

TWAI

No

No

No

UART

Yes

Yes

Yes

USB

Not Supported

Yes

Yes

ESP32-C3 only CDC/JTAG

Wi-Fi

Yes

Yes

Yes

Notes[¶](https://docs.espressif.com/projects/arduino-esp32/en/latest/libraries.html#notes)

(*) SPI Ethernet is supported by all ESP32 families and RMII only for ESP32.

Note

Some peripherals are not available for all ESP32 families. To see more details about it, see the corresponding SoC at [Product Selector](https://products.espressif.com/) page.
Datasheet[¶](https://docs.espressif.com/projects/arduino-esp32/en/latest/libraries.html#datasheet)

    [ESP32](https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf) (Datasheet)

    [ESP32-S2](https://www.espressif.com/sites/default/files/documentation/esp32-s2_datasheet_en.pdf) (Datasheet)

    [ESP32-C3](https://www.espressif.com/sites/default/files/documentation/esp32-c3_datasheet_en.pdf) (Datasheet)

    [ESP32-S3](https://www.espressif.com/sites/default/files/documentation/esp32-s3_datasheet_en.pdf) (Datasheet)

APIs[¶](https://docs.espressif.com/projects/arduino-esp32/en/latest/libraries.html#apis)

The Arduino ESP32 offers some unique APIs, described in this section:

    [ADC](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/adc.html)
    [Bluetooth API](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/bluetooth.html)
    [DAC](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/dac.html)
    [Deep Sleep](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/deepsleep.html)
    [ESP-NOW](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/espnow.html)
    [GPIO](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/gpio.html)
    [I2C](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/i2c.html)
    [I2S](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/i2s.html)
    [LED Control (LEDC)](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/ledc.html)
    [Preferences](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/preferences.html)
    [RainMaker](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/rainmaker.html)
    [Reset Reason](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/reset_reason.html)
    [SigmaDelta](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/sigmadelta.html)
    [Timer](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/timer.html)
    [USB API](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/usb.html)
    [USB CDC](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/usb_cdc.html)
    [USB MSC](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/usb_msc.html)
    [Wi-Fi API](https://docs.espressif.com/projects/arduino-esp32/en/latest/api/wifi.html)
lbernstone commented 1 year ago

\<thread> is a C-std library. https://www.tutorialspoint.com/cpp_standard_library/thread.htm pthread is the esp-idf implementation of posix threads. https://docs.espressif.com/projects/esp-idf/en/latest/esp32s2/api-reference/system/pthread.html Since these are not part of the Arduino standard, they are not documented in this repo.

Rotzbua commented 1 year ago

@lbernstone Thread is also an iot network protocol. @dsyleixa You have to specify which thread you mean. Process or network related?

dsyleixa commented 1 year ago

I mean ESP32 std::thread and pthread-like impementations for multitasking, but which are not 100% identical to POSIX- or C++14 std::thread (BTW, <thread> is from C++, not C, and neither is Arduino-API-standard) as to https://www.tutorialspoint.com/cpp_standard_library/thread.htm https://docs.espressif.com/projects/esp-idf/en/latest/esp32s2/api-reference/system/pthread.html this is basically what I was searching, albeit still missing program examples like provided for all the other libraries (in the libraries examples folders), and some things like thread prios have a very special design...

me-no-dev commented 1 year ago

this seems quite a bit out of the scope of Arduino to explain or show examples.

dsyleixa commented 1 year ago

My point is: Which is deviating from the C++ and POSIX standards, and what is fully standard compliant? (e.g., mutex, thread prios, detached, joinable, get_id, native_handle, atomic, delay vs. std::this_thread::sleep_for vs. usleep vs. nanosleep,...) And finally no single example is shown and/or explained about anything of threads, and IIUC, there is quite a bunch of peculiarities in the implementation for RTOS.

me-no-dev commented 1 year ago

I get your point, but what you ask about is outside of the scope of Arduino. You can ask about this in ESP-IDF and/or Espressif's crosstool-NG repositories. We use FreeRTOS tasks in ESP32 Arduino, because we are running on FreeRTOS and have no way around it. Generally Arduino is single-threaded framework.

dsyleixa commented 1 year ago

My question is not about standard Arduino API but about the special std::thread a/o pthread implementation by the arduino-esp32 API, and so my interest in documentations, explanations, and examples is 100% on-topic and fully justified IMO.

me-no-dev commented 1 year ago

I'm not sure you understand what is Arduino and what is not. Your questions are about ESP-IDF and the toolchain, not about what is implemented in Arduino. Arduino implementations are in the core and libraries folder of this repo. Everything outside of those 2 folders is not Arduino.

dsyleixa commented 1 year ago

well, I am using the thread functions (e.g. std::thread(), thread.join(), standard::mutex,...) by the Arduino IDE, the Arduino API and the entire Arduino ecosystem, so my question is finally exactly concerning this arduino-esp32 repo, and I do not use ESP-IDF at all. And when you mention "Arduino" you better should write clearly if you mean the Arduino ecosystem (by Arduino.cc) or your arduino-esp32 API (for/by espressif).

me-no-dev commented 1 year ago

I'm always happy to be schooled on what is Arduino API and what is not :) Maybe someone more knowledgable on this topic than me will be able to answer your questions.

PilnyTomas commented 1 year ago

If you are using ESP chips with Arduino IDE then 100% you ARE using ESP-IDF, it is just hidden in arduino-esp32. It would not make sense to repeat documentation for the entire ESP-IDF here.

dsyleixa commented 1 year ago

well, I am asking because I am searching example code which can be compiled by the Arduino IDE, i.e. Arduino examples of *.ino type (just like all your other examples about FS, i2s, WiFi, SD, Wiire, whatever), and also docs about which single (std::) thread functions are available by which Arduino syntax. OTOH, AFAIK not all ESP-IDF functions are available also for arduino-esp32 as well, so it's just a subset (CMIIW)

me-no-dev commented 1 year ago

So you are looking for something like this: https://github.com/espressif/arduino-esp32/blob/master/libraries/ESP32/examples/FreeRTOS/FreeRTOS.ino

dsyleixa commented 1 year ago

basically yes, but using std::thread and std::mutex, not RTOS functions.

me-no-dev commented 1 year ago

what's wrong with RTOS functions? This is what we run on and what we support. For other things, you are on your own (since you refuse to ask your questions in the relevant repositories).

dsyleixa commented 1 year ago

I don't use this RTOS low-level stuff at all, I am only using C++ std:: class syntax which is intuitive, common, popular, and handy (also for RaspberryPi/Linux) (same as to POSIX pthread). And as it's available for ESP32, too, I was searching the related docs and examples.

me-no-dev commented 1 year ago

Use whatever you want. That is up to you. Just don't expect to find help about that here :) We use FreeRTOS and it's functions. Regardless how many times you say that "it's included", it will not make std::thread be part of Arduino or it's APIs.

Docs for pthread: https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/system/pthread.html Fourth paragraph reads:

C++ Standard Library implementations for std::thread, std::mutex, std::condition_variable, etc. are implemented using pthreads (via GCC libstdc++). Therefore, restrictions mentioned here also apply to the equivalent C++ standard library functionality.
dsyleixa commented 1 year ago

the esp32 syntax is different from standard C/C++. e.g., for prios and parameters the standard syntax is (optionally/arbitrarily)

std::thread thread0 (foo); 
param.sched_priority = 50;   
pthread_setschedparam(thread0.native_handle(), SCHED_RR, &param);

or e.g.

std::thread t1 (foo);
CPU_ZERO(&cpus);  // Clear the set of cpus   
core=1;           
CPU_SET(core, &cpus);     
pthread_setaffinity_np( t1.native_handle(), sizeof(cpu_set_t), &cpus );

this syntax is not possible for arduino-esp32 (IIUC, CMIIW). So I was searching the related docs and examples.

me-no-dev commented 1 year ago

Syntax is not possible not in Arduino but in ESP-IDF. Since Arduino is on top of ESP-IDF, would it not make sense to actually ask there? I really struggle to understand your reluctance to go and ask at the correct place...

dsyleixa commented 1 year ago

as you said, Syntax is not possible not in Arduino but in ESP-IDF. so as I am just using arduino-esp32 it would make no sense to ask in ESP-IDF, does it? And are there *.ino examples in ESP-IDF? (I guess: no). So what is so hard to understand when I ask about docs and ino examples for arduino-esp32 here in the arduino-esp32 repo?

me-no-dev commented 1 year ago

My English is obviously too limited to explain that to you, so I will just stop answering and leave it up to chance that someone here might be able to help you :)

dsyleixa commented 1 year ago

perhaps your English is also too limited to understand what I mean, so why do you add "wontfix" in case you lack of comprehension?

igrr commented 1 year ago

Hi @dsyleixa, even though we don't have an Arduino-specific example for threads yet, please take a look at this example in IDF: https://github.com/espressif/esp-idf/blob/009d15e59db4f50fcf08849f14427c8ebbc1aff4/examples/cxx/pthread/main/cpp_pthread.cpp#L88-L90. I think it should be quite similar in Arduino.

Creation of threads is as usual in C++ standard (use std::thread constructor)

To set thread priority, stack size, name, affinity and so on, call esp_pthread_set_cfg function before starting the thread. The function is defined in #include "esp_pthread.h". The example I have linked shows a few ways how you can obtain the esp_pthread_cfg_t argument you should pass to this function.

Edit: I've also taken note about pthread_setaffinity_np not working right now. We'll see if we can make it work in ESP-IDF, so that you can use standard APIs as you have shown in https://github.com/espressif/arduino-esp32/issues/7394#issuecomment-1291968243.

dsyleixa commented 1 year ago

thanks a lot for your examples, An easier Arduino example for the start (showing even some extra features) might be:

// std::thread for ESP32, Arduino IDE

// thread loops can be exited by internal conditions (e.g. via break or return) 
// or all inner loops by setting THREADRUN=false at any location.

#include <Arduino.h>
#include <thread>
#include <freertos/task.h>
#include <esp_task.h>

using namespace std;

volatile static bool THREADRUN = true;

//--------------------------------------------------------------------
void function2() {
   vTaskPrioritySet( NULL, ESP_TASK_MAIN_PRIO ); // set Priority = main prio   
   Serial.println((String)"   function2 started"); 
   while(THREADRUN) {      
      // do stuff
   }
   Serial.println((String)"   function2 terminating"); 
}

//--------------------------------------------------------------------

void function1() {
   vTaskPrioritySet( NULL, ESP_TASK_MAIN_PRIO ); // set Priority = main prio   
   Serial.println((String)"   function1 started"); 
   while(THREADRUN) {      
      // do stuff
   }
   Serial.println((String)"   function1 terminating"); 
}

//--------------------------------------------------------------------

void function0() {
   vTaskPrioritySet( NULL, ESP_TASK_MAIN_PRIO ); // set Priority = main prio 
   Serial.println((String)"   function0 started"); 
   while(THREADRUN) {      
      // do stuff
   }
   Serial.println((String)"   function0 terminating"); 
}

//--------------------------------------------------------------------
//--------------------------------------------------------------------
void setup() {
   Serial.begin(115200);

   thread thread_0 (function0);
   thread thread_1 (function1);
   thread thread_2 (function2);

   Serial.println((String)"\n all threads being started, now waiting for all being terminated and to join main thread \n");  // <<<<<<  

   thread_0.join();
   thread_1.join();
   thread_2.join();

   Serial.println((String)"\n all threads joined, program terminated\n");  // <<<<<<  
}

//--------------------------------------------------------------------
void loop() { // empty placeholder for Arduino compatibility
   // when using repetitive code also in the standard loop() then this loop won't terminate after main/setup has finished
}

And now my question is about a list of available functions (simple and advanced features) and step-by-step examples to show either esp32 feature in ino files, ready to compile. No problem if there is one or the other feature not available or under construction, but one should have the chance to see what's there and what not and how to use it, like shown e.g. in the cplusplus.com or QNX.com examples: https://cplusplus.com/reference/thread/thread/ http://www.qnx.com/developers/docs/6.5.0/index.jsp?topic=%2Fcom.qnx.doc.neutrino_lib_ref%2Fp%2Fpthread_create.html

Finally it's not just for me but for all Arduino users, starting into multithreading.

(just a proposal, I would appreciate if the esp-pthread functions looked exactly like the related original POSIX pthread ones)

igrr commented 1 year ago

As @me-no-dev has mentioned above, the arduino-esp32 team doesn't consider "C++ std::thread" as something that needs to be exposed or recommended to Arduino users. This is based on the fact that the other available Arduino cores don't do that either. Hence even if multithreading support happens to work, it's not something that is considered to be in the scope of the project.

That evaluation may change in the future if there are more than a few people asking for this. The monthly Community Meetings are a great way to share your ideas and exchange views with other community members, to eventually push such topics forward!

dsyleixa commented 1 year ago

ok, perhaps not about the simple std::thread needed, but for all the rest, when it comes e.g. to prios, pthread_join(), pthread_detach(), pthread_exit(), sched_yield(), ...., and CPU_SET (some day), Most of the Arduino-esp-users do not even know that std::thread is available at all. So some simple examples would be precious though. And documentations about all and everything. (PS, and having std::thread is such a powerful tool that it will make millions of M1, M4, and RP2040 users migrate to ESP32: I know how much that is actually needed in the community.)

SuGlider commented 1 year ago

I can see that @dsyleixa is participating on the Arduino Thread discussion https://github.com/arduino/language/discussions/2

@dsyleixa - Arduino proposed this library as an Arduino-Style API for MultiTasking: https://github.com/arduino-libraries/Arduino_Threads https://github.com/arduino-libraries/Arduino_Threads/blob/main/docs/threading-basics.md

Do you see that as an "Arduino Way" for implementing Threads? Arduino_Threads Library seems more "Arduinoish" than std::thread and FreeRTOS API.

dsyleixa commented 1 year ago

IMO the current "Arduinish MT" is not suitable,and a "new" Arduinish API style is not needed at all. As I already have stated, I understand that Arduino often does not use standardized C/C++ lib syntax for reasons of simplicity (e.g., digitalRead/Write, analogRead/Write, delay). But std::thread / std::mutex are already very easy, handsome, logical, suitable, and very common, so IMO there is no need to invent another API syntax from the scratch with only doubtfully (and falsely claimed) better usability or benefits. How easy std:thread actually is I have already shown above https://github.com/espressif/arduino-esp32/issues/7394#issuecomment-1292166967 What I can see what the Arduino devs currently try to achieve for their proprietary boards (ARM M1, M4, H7) is still in its early infancy and is quite a bit of gibberish and hotchpotch, tbh - and also supports only MT on one single core. So IMO there is no reason for an Arduinish lib, std::thread (plus some standard POSIX pthread commands for advanced optional configuration) is absolutely fine and absolutely suitable for beginners to multithreading, and the confusing low-level RTOS stuff behind and underneath can be perfectly hidden for the end-users - for esp32-arduino it just lacks of documentations and examples.

VojtechBartoska commented 1 year ago

@dsyleixa Can you help with your contribution to this? It seems it's more obvious to you than to us. Contribution to documentation is very welcomed, we don't have them so often unfortunately. :)

dsyleixa commented 1 year ago

My reply was related to SuGlider's comment

Do you see that as an "Arduino Way" for implementing Threads?
Arduino_Threads Library seems more "Arduinoish" than std::thread and FreeRTOS API.

I think what Arduino.cc is trying to do is just nonsense and they better should use std::thread syntax as well.

OTOH, what I am missing here in this https://github.com/espressif/arduino-esp32 repo is: I am missing a couple of Arduino-API-examples in your repo directory https://github.com/espressif/arduino-esp32/tree/master/libraries about std::thread usage including mutexes, semaphores, thread prios, cpu-core assignment, suitable for tutorial purposes how to use multithreading accordingly. For WiFi, SD, or SPI there are lots of examples, for multithreading nothing (found). so for std::thread I would have expected a sub-folder - perhaps called "multithreading" - providing step-by-step examples, usable as a tutorial for beginners.

My own examples are most probably not suitable for general usage, but you may find some personal approaches in here: https://github.com/dsyleixa/Arduino/tree/master/ESP32_Test