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How can I show that assignment is not atomic?


By : Linux_Wangpeng
Date : July 30 2020, 11:00 AM
I wish did fix the issue. Grab the disassembly and then check the documentation for your architecture; on some machines you'll find even standard "non-atomic" operations (in terms of C++) are actually atomic when it hits the hardware (in terms of assembly).
With that said, your compiler will know what is and isn't safe and it is therefore a better idea to use the std::atomic template to make your code more portable across architectures. If you're on a platform that doesn't require anything special, it'll typically get optimised down to a primitive type anyway (putting memory ordering aside).
code :


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Is compound assignment ^= atomic in C#?


By : user3167192
Date : March 29 2020, 07:55 AM
it fixes the issue As answered above, x^=1 is not atomic. Could you use Interlocked.Increment (which is atomic) and then, when reading, consider the value % 2?

Python: conversion of a iterated assignment with an atomic assignment using numpy is not working when matrix height >


By : user2519149
Date : March 29 2020, 07:55 AM
seems to work fine I get the problem!
I cast the matrix I to uint8 and so matrix I elements are between 0 and 255.

What does assignment mean to a C11 atomic?


By : bhag jathol
Date : March 29 2020, 07:55 AM
like below fixes the issue Operations on objects that are _Atomic qualified (and atomic_int is just a different writing for that) are guaranteed to have sequential consistency. You find that mentionned at the end of the semantics section for each of the operands. (And maybe the mention for assignment is missing.)
Your code is not correct at two places: initialization must use the ATOMIC_VAR_INIT macro (7.17.2.1), and memcpy is undefined (the sizes might not agree), although it probably will work on most of the architectures.
code :
tmp = mc + 4;                // Arithmetic
mc += 4;                // Arithmetic

C# Is value type assignment atomic?


By : user2145915
Date : March 29 2020, 07:55 AM
this will help Structs are value types. If you assign a struct to a variable/field/method parameter, the whole struct content will be copied from the source storage location to the storage location of the variable/field/method parameter (the storage location in each case being the size of the struct itself).
Copying a struct is not guaranteed to be an atomic operation. As written in the C# language specification:

Are assignment = and subtraction assignment -= atomic operations in C?


By : belrod
Date : March 29 2020, 07:55 AM
I hope this helps you . It depends on the implementation. By the standard, nothing is atomic in C. If you need atomic ops you can look at your compiler's builtins.
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