CODEWITHSUNDEEP
cmultithreadingwinapi
Christopher
Christopher

Reputation: 799

How to allow two threads to share a global variable in WinAPI?

I have two threads that are created using CreateThread(), and I have a global variable that one thread writes to, and the other thread reads from.

Now based on my understanding, the compiler and/or the CPU can do all sorts of optimizations, which could mean for example that when I write a value to the variable, the value can be written in some cache and not written directly to memory (and hence the other thread will not be able to see it).

I have read that I can wrap the code that access the variable in a critical section, but the documentation says that a critical section will only enforce mutual exclusion, and does not say anything about enforcing writing directly to memory and reading directly from memory.

Note that I do not which to use the volatile keyword, I want to know how this is done in pure WinAPI (as I could use a language other than C in a later time).

Upvotes: 0

Views: 1179

Answers (1)

Sergei Vorobiev
Sergei Vorobiev

Reputation: 374

MSDN explicitly states that critical sections are memory barriers. https://msdn.microsoft.com/en-us/library/windows/desktop/ms686355(v=vs.85).aspx

Upvotes: 2

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