How to return a variable from a function in a multi core environment?

Question

So i have a variable which must be available to other tasks in the system. I have a function which should return this variable so other tasks can do their thing according to this variable.

boolean pSystem::isLowPower(){
    return LOW_POWER;
}

If i use it RAW or trought the function, I got an IllegalInstruction error from a random task that wants to use this variable and my ESP crashes.

So if i want to guard this variable with a mutex i couldn't return it.

boolean pSystem::isLowPower(){
    xSemaphoreTake( testMutex );
    return LOW_POWER;
    xSemaphoreGive( testMutex  ); // Will not release?
}

How can i guard this variable and return it at the same time?

The use case would be only something like this:

void TaskOne(void* parameter){
    for(;;){
        if( Preformance.isLowPower() ){ vTaskDelay(100); return; }
        // Do other task related stuffs...
        vTaskDelay(1);
    }
}

void TaskTwo(void* parameter){
    for(;;){
        if( Preformance.isLowPower() ){ vTaskDelay(100); return; }
        // Do other task related stuffs...
        vTaskDelay(1);
    }
}

The error log i got ( from random tasks )

Guru Meditation Error: Core  0 panic'ed (IllegalInstruction). Exception was unhandled.
Memory dump at 0x400f1034: 08e08096 00f01d00 257bfea1
Core  0 register dump:
PC      : 0x400f1039  PS      : 0x00060430  A0      : 0x00000000  A1      : 0x3ffd2b50
A2      : 0x00000000  A3      : 0x00000000  A4      : 0x00000000  A5      : 0x00000000
A6      : 0x00000000  A7      : 0x00000000  A8      : 0x800f1039  A9      : 0x3ffd2b30
A10     : 0x00000064  A11     : 0x3ffbf638  A12     : 0x3ffbdd58  A13     : 0x0000000a
A14     : 0x0000000a  A15     : 0x80000001  SAR     : 0x00000000  EXCCAUSE: 0x00000000
EXCVADDR: 0x00000000  LBEG    : 0x00000000  LEND    : 0x00000000  LCOUNT  : 0x00000000  


Backtrace: 0x400f1036:0x3ffd2b50

  #0  0x400f1036:0x3ffd2b50 in mBusLoopTask(void*) at src/utilities/modBus.cpp:1495 (discriminator 1)




ELF file SHA256: 1c0b237e74fe9d04

Rebooting...

Answer 1

So the problem was that i wanted to return from the task without deleting it and it produced the IllegalInstruction error.

The solution is to not return but continue the loop

void TaskOne(void* parameter){
    for(;;){
        if( Preformance.isLowPower() ){ vTaskDelay(100); continue; }
        // Do other task related stuffs...
        vTaskDelay(1);
    }
}

OR

void TaskTwo(void* parameter){
    for(;;){
        if( !Preformance.isLowPower() ){
            // Do other task related stuffs...
        }else{
            vTaskDelay(100);
        }
        vTaskDelay(1);
    }
}