lock semantics question

Question

5.00/5 (2 votes)

See more:

Say we have the following:

C#

private object _lock = new object();
public void A()
{
   lock(_lock)
   {
       // do something critical
       B();
   }
}

public void B()
{
   // do something else
}

And we call the A method from Tasks or Threads does the lock operation block cover the B method call also i.e. B calls are also serialized?

(I seem to have weird things going on which can only be explained by the B method not happening in the lock - or I could be mistaken).

Posted 14-Mar-12 23:11pm

Mehdi Gholam

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Abhinav S · Accepted Answer · 2012-03-14T23:30:00

Solution 1

No. The method B is not covered.

The lock statement makes sure that when two callers call A, one of the executes B and completes before the other one starts execution (of the code within the lock statement).

B could actually be called from anywhere else in the application (not by calling A) and there would be nothing stopping from executing it!

Posted 14-Mar-12 23:30pm

Abhinav S

Updated 14-Mar-12 23:31pm

v2

Comments

Mehdi Gholam 15-Mar-12 5:45am

B is only being called from A and not directly. B is actually a filestream write and I am getting corrupt data in the stream.

Abhinav S 15-Mar-12 5:59am

Sounds strange but why don't you move the lock around B and give it a try? Sometimes strange things work! :)

Mehdi Gholam 15-Mar-12 6:08am

I have, it's the same. Maybe my read and write streams are out of sync?

Abhinav S 15-Mar-12 7:04am

Possibly.

Mehdi Gholam 16-Mar-12 3:45am

Found the bug, it was the stream flushing, I removed it and it works fine now.

Abhinav S 16-Mar-12 9:45am

Cool.