c# - understanding of Volatile.Read/Write -

c# - understanding of Volatile.Read/Write -

i'm trying understand c# volatile class.

as read:

the volatile.write method forces value in location written @ point of call. in addition, before program-order loads , stores must occur before phone call volatile.write.

the volatile.read method forces value in location read @ point of call. in addition, later program-order loads , stores must occur after phone call volatile.read.

is means in case of:

internal sealed class threadssharingdata { private int32 m_flag = 0; private int32 m_value = 0; // method executed 1 thread public void thread1() { // note: 5 must written m_value before 1 written m_flag m_value = 5; volatile.write(ref m_flag, 1); } // method executed thread public void thread2() { // note: m_value must read after m_flag read if (volatile.read(ref m_flag) == 1) console.writeline(m_value); } }

the cpu wait commands before volatile.write(ref m_flag, 1); before starting write m_flag?

and how helps threads synchronization?

the cpu wait commands before volatile.write(ref m_flag, 1); before starting write m_flag?

eeeh, kinda. improve way phrase is: it's guaranteed that, if other thread sees m_flag set 1, see m_value set 5.

and how helps threads synchronization?

i wouldn't helps synchronization - help achieving correctness.

if weren't using volatile reads/writes, possible compiler/runtime/cpu reorder 2 instructions in thread1 method, , programme able print either 0, 5 or nil @ all.

with volatile reads/writes, programme print either 5 or nil @ all, never 0. intended behaviour.

c# volatile thread-synchronization