Multithreading in C ++

Multithreading in C ++
Zookeeper

1. Multithreading

Multithreading case:

# Include

# Include

# Include

# Include

Usingnamespacestd;

Voidrun (intnum)

{

Sleep (1000 );

Std: cout <"Hello tianchao" <num <

}

Voidmain ()

{

Thread * p [10];

For (inti = 0; I <10; I ++)

{

P [I] = newthread (run, I); // create a thread cyclically

// P [I]-> join (); // wait, equivalent to blocking

P [I]-> detach (); // execute freely from the current main thread in disorder. That is to say, the execution of each thread is random and is executed concurrently.

}

Cin. get ();

}

The running result is:

2. Thread case 2

# Include

# Include

# Include

# Include

Usingnamespacestd;

Voidhelloworld ()

{

Std: cout <"" <endl;

}

VoidhelloworldA ()

{

Std: cout <" A" <endl;

}

VoidhelloworldB ()

{

Std: cout <" B" <endl;

}

// The threads implemented in the following way are always sequential.

Voidmain ()

{

Std: threadt1 (helloworld); // sequential thread execution

Std: threadt2 (helloworldA );

Std: threadt3 (helloworldB );

Cin. get ();

}

3. thread locking and thread unlocking

# Include

# Include

# Include

# Include

# Include

Usingnamespacestd;

// Two threads access a variable in parallel

Intg_num = 20; // The identifier that cannot be found or found.

Mutexg_mutex;

VoidgoA (intnum)

{

// The variables you access, which cannot be accessed by others during your access,

// In this case, you can see that you have been executed more often.

G_mutex.lock ();

For (inti = 0; I <15; I ++)

{

Sleep (300 );

G_num = 10;

Std: cout <"Thread" <num <"" <

}

G_mutex.unlock ();

}

VoidgoB (intnum)

{

For (inti = 0; I <15; I ++)

{

Sleep (500 );

G_num = 11;

Std: cout <"Thread" <num <"" <

}

}

Voidmain ()

{

Threadt1 (goA, 1 );

Threadt2 (goB, 2 );

T1.join ();

T2.join ();

Std: cin. get ();

}

Running result:

4. Communication and lock between threads <喎?http: www.bkjia.com kf ware vc " target="_blank" class="keylink"> Vcd4kcjxwprc4wp2juw.vcd4kcjxwiggfsawdupq = "left"> # include

# Include

# Include

# Include

Usingnamespacestd;

// Two threads access a variable in parallel

// The ID that is found or cannot be found

Intg_num = 20;

VoidgoA (intnum)

{

For (inti = 0; I <15; I ++)

{

Sleep (1000 );

If (I = 6)

{

G_num = 5;

}

If (g_num = 5)

{

Std: cout <"Thread" <num <"End \ n ";

Return;

}

Std: cout <"Thread" <num <"" <

}

}

VoidgoB (intnum)

{

For (inti = 0; I <150; I ++)

{

Sleep (1000 );

If (g_num = 5)

{

Std: cout <"Thread" <num <"End \ n ";

Return;

}

Std: cout <"Thread" <num <"" <

}

}

Voidmain ()

{

Threadt1 (goA, 1 );

Threadt2 (goB, 2 );

T1.join ();

T2.join ();

Std: cin. get ();

}