Hi there, straight to the point.
I'm trying to use wificlientsecure to make some https requests, I want these requests to run on the esp32's second core, so they're not blocking the main thread.
But I've run into some problems trying to put the following sketch into a class.
I've removed anything not directly related to my problem, so theres no http requests being done here. It will do some work on the second core, write the result in a shared variable, and set a flag indicating it's done. Main loop thread checks the indicator and reads the result variable when its complete. To hopefully make it thread safe.
ESP32CoreTaskTest.ino
//Global Variables shared between cores
bool taskFinished = false;
int count = 0;
void setup() {
//Start Serial Output
Serial.begin(115200);
Serial.println("");
xTaskCreatePinnedToCore(
task, //Function to implement the task
"taskname", //Name of the task
6000, //Stack size in words
NULL, //Task input parameter
0, //Priority of the task
NULL, //Task handle.
1); //Core where the task should run
}
void loop() {
// put your main code here, to run repeatedly:
if(taskFinished){
Serial.print("Task#: ");
Serial.println(count);
}else{
Serial.println("Busy");
}
delay(100);
}
void task( void* ){
while(1){
taskFinished = false;
count++; //do some work
delay(250); //do some work
taskFinished = true;
delay(250); //Pretend task is done, and not really looping. We should be able to read the task result after the task has finished
}
}
This works perfectly, they share memory and wait for tasks to be finished before reading the result.
But I cannot figure out how implement it as a class. So I can use it like this.
Task task = Task();
task.startTask();
while(!task.taskFinished)
{
//busy
}
int result = task.count;
//Dispose the task, keep the result
Obviously the code works, so it must be turned into c++ at some point, but I dont know what that would look like.
My attempt at the code looks like this:
ESP32CoreTaskTest_Class.ino
#include "Task.h"
Task task;
void setup() {
//Start Serial Output
Serial.begin(115200);
Serial.println("");
task = Task();
task.startTask();
}
void loop() {
// put your main code here, to run repeatedly:
if(task.taskFinished){
Serial.print("Task#: ");
Serial.println(task.count);
}else{
Serial.println("Busy");
}
delay(100);
}
Task.cpp
#include "Task.h"
//Constructor
Task::Task(){
}
//Member
void Task::startTask(){
xTaskCreatePinnedToCore(
this->worktask, //Function to implement the task
"taskname", //Name of the task
6000, //Stack size in words
NULL, //Task input parameter
0, //Priority of the task
NULL, //Task handle.
1); //Core where the task should run
}
//Task to run
void Task::worktask(void* _this){
while(1){
taskFinished = false;
count++; //do some work
delay(250); //do some work
taskFinished = true;
delay(250); //Pretend task is done, and not really looping. We should be able to read the task result after the task has finished
}
}
Task.h
#ifndef Task_h
#define Task_h
#include "Arduino.h"
class Task {
public:
Task(void);
void startTask(void);
bool taskFinished = false;
int count = 0;
private:
static void worktask( void* );
};
#endif
This throws "invalid use of member 'Task::taskFinished' in static member function" as described in the link below.
As its not quite as simple as just making it a static member. 
https://esp32.com/viewtopic.php?t=5027 that I cant quite decipher.
And I did try what was suggested, but I ran into some different compile errors, so I thought I'd go back to my orignal question to myself, and post it here.
What would my original sketch look like, if it was plain c++?