volatile and thread safety

[arun.darra]

Hi,

Is the following thread safe??

class Sample
{
private:
volatile int number;
public:
Sample():number(0) {}

void read()
{
++number;
// do nothing
--number;
}
};

I would like to know if the function read() were executed by multiple
threads simultaniously, would function be thread safe?
I mean would the ++ and -- operation be tomic?

Thanks

 

[Gianni Mariani]

Hi,

Is the following thread safe??

class Sample
{
private:
volatile int number;
public:
Sample():number(0) {}

void read()
{
++number;
// do nothing
--number;
}
};

I would like to know if the function read() were executed by multiple
threads simultaniously, would function be thread safe?
NO.

I mean would the ++ and -- operation be tomic?

NO.

Try comp.programming.threads.

 

[Ian Collins]

NO.

Try comp.programming.threads.

Where this question has been asked and done to death often, so check the
group's archives first.

 

[Ge Chunyuan]

I would like to know if the function read() were executed by multiple

threads simultaniously, would function be thread safe?

Of course not!

I mean would the ++ and -- operation be tomic?

No, why not try mutex?
there are lots of sample all around

Ge Chunyuan