question about objects by reference and threadsafety

[john smith]

If I create an object and pass it by reference to two other functions, and
the other two function have separate threads
must I worry about threadsafety? The two functions could modify the myCar
object in main at the same time couldn't they?

I have trouble understading if this is a problem or not. both functions
reference the myCar object in main and could potentially create a critical
section
path correct?
Thanks.

For example

int main()
{

Car myCar;

fixCar( myCar ); // fixCar() is a process running on its
own thread

fixCarAgain( myCar ); // fixCarAgain() is a process running on its
own thread

return 0;

}

void fixCar( Car& myCar ) // separate thread
{
// if I modify myCar should I do mutual exclusion semaphore here?

}

void fixCarAgain( Car& myCar ) // separate thread
{
// if I modify myCar should I do mutual exclusion semaphore here?

}

[shez]

john smith wrote:

int main()
{

Car myCar;

fixCar( myCar ); // fixCar() is a process running on its own thread

fixCarAgain( myCar ); // fixCarAgain() is a process running on its own thread

return 0;

}

void fixCar( Car& myCar ) // separate thread
{
// if I modify myCar should I do mutual exclusion semaphore here?

}

void fixCarAgain( Car& myCar ) // separate thread
{
// if I modify myCar should I do mutual exclusion semaphore here?

}

Yes, you will need a mutex if you modify myCar.

-shez-