Crash and semaphores

Thank you for the interesting.

The code is:

#include "includes.h"

#include <iostream>

using namespace std;

#define OS_TASK_STAT_EN 1

#define OS_MAX_TASKS 8

#define TASK_STK_SIZE 1024

OS_STK TaskStartStk[TASK_STK_SIZE];

OS_STK TaskStartStk1[TASK_STK_SIZE];

OS_STK TaskStartStk2[TASK_STK_SIZE];

OS_STK TaskStartStk3[TASK_STK_SIZE];

OS_EVENT* sem_sync0;

OS_EVENT* sem_sync1;

OS_EVENT* sem_sync2;

OS_EVENT* sem_sync3;

void handle_sync(void* pdata) {

INT8U err_sync3;

pdata = pdata;

for(;;) {

cout << "I'm in handle_sync" << endl;

fflush(0);

OSSemPost(sem_sync1);

OSSemPend(sem_sync3, 0, &err_sync3);

}

}

void processing(void* pdata) {

INT8U err_sync1;

pdata = pdata;

for(;;) {

cout << "I'm in processing" << endl;

fflush(0);

OSSemPost(sem_sync2);

OSSemPend(sem_sync1, 0, &err_sync1);

}

}

void monitoring(void* pdata) {

INT8U err_sync2;

pdata = pdata;

for(;;) {

cout << "I'm in monitoring" << endl;

fflush(0);

OSSemPost(sem_sync3);

OSSemPend(sem_sync2, 0, &err_sync2);

}

}

static void TaskStartCreateTask(void) {

cout << "I'm in TaskStartCreateTask" << endl;

fflush(0);

OSTaskCreate(handle_sync, (void*) 0, &TaskStartStk1 [TASK_STK_SIZE - 1], 11);

OSTaskCreate(processing, (void*) 0, &TaskStartStk2[TASK_STK_SIZE - 1], 12);

OSTaskCreate(monitoring, (void*) 0, &TaskStartStk3[TASK_STK_SIZE - 1], 15);

}

void TaskStart(void* pdata) {

INT8U err_sync0;

cout << "I'm in TaskStart" << endl;

fflush(0);

pdata = pdata;

OSStatInit();

OSTaskCreate(handle_sync, (void*) 0, &TaskStartStk1[TASK_STK_SIZE - 1], 11);

OSTaskCreate(processing, (void*) 0, &TaskStartStk2[TASK_STK_SIZE - 1], 6);

OSTaskCreate(monitoring, (void*) 0, &TaskStartStk3[TASK_STK_SIZE - 1], 15);

for(;;) {

OSSemPost(sem_sync3);

OSSemPend(sem_sync0, 0, &err_sync0);

}

}

int main()

{

OSInit();

sem_sync0 = OSSemCreate(0);

sem_sync1 = OSSemCreate(0);

sem_sync2 = OSSemCreate(0);

sem_sync3 = OSSemCreate(0);

cout << "I'm in the main" << endl;

fflush(0);

OSTaskCreate(TaskStart, (void*) 0, &TaskStartStk[TASK_STK_SIZE - 1], 18);

OSStart();

}

If I put the semaphore in this way:

OSSemPend(sem);

cout << "Hello world" << endl;

OSSemPost(sem, 0, err);

does it become thread safe?

Thanks

Yes, as long as you do that in every thread that uses the standard output, and that you use the same semaphore on each, obviously.

I re-read your code and I'm wondering something... where do you post your semaphore sem_sync0 ?

What are you trying to achieve in this code?

I don't post sem_sync0 because I want that TaskStart creates the other tasks and stops: sem_sync0 never becomes 1, then TaskStart never runs, only at the beginning. But I don' think that this is the problem, because the same problem is verified when the three tasks are created in the main and not in TaskStart, i.e. when there isn't the thread TaskStart.

Thanks

A task can kill itself with OsTaskDel(OS_PRIO_SELF);

After this call the task will be deleted.

Did you see any improvement by using this semaphore to make the standard output thread safe?