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Why is the variable state declared as volatile?
Declaring a variable volatile is a directive to the compiler. A variable should be declared volatile whenever its value can be changed by something beyond the control of the code section in which it appears, such as a concurrently executing thread.
What is a volatile pointer?
A pointer of the form. volatile int* p; is a pointer to an int that the compiler will treat as volatile . This means that the compiler will assume that it is possible for the variable that p is pointing at to have changed even if there is nothing in the source code to suggest that this might occur.
Why to use volatile variable in C?
C’s volatile keyword is a qualifier that is applied to a variable when it is declared. It tells the compiler that the value of the variable may change at any time–without any action being taken by the code the compiler finds nearby.
What is a volatile variable in C?
A volatile keyword in C is nothing but a qualifier that is used by the programmer when they declare a variable in source code. It is used to inform the compiler that the variable value can be changed any time without any task given by the source code. Volatile is usually applied to a variable when we are declaring it.
What is the purpose of a volatile variable?
Volatile keyword is used to modify the value of a variable by different threads. It is also used to make classes thread safe. It means that multiple threads can use a method and instance of the classes at the same time without any problem. The volatile keyword can be used either with primitive type or objects.
Why is volatile used?
volatile is a qualifier that is applied to a variable when it is declared. It tells the compiler that the value of the variable may change at any time-without any action being taken by the code the compiler finds nearby.
Can we use const and volatile together?
Yes. A variable can be declared as both volatile and constant in C. Const modifier does not allow changing the value of the variable by internal program. But, it does not mean that value of const variable should not be changed by external code.
What is volatile where is it used?
The volatile keyword is intended to prevent the compiler from applying any optimizations on objects that can change in ways that cannot be determined by the compiler. Objects declared as volatile are omitted from optimization because their values can be changed by code outside the scope of current code at any time.
Where is volatile used?
What is the difference between static and volatile variable?
A static variable refers to a class variable that’s shared among all instances. volatile: Volatile variables are those which are read and written to main memory. They aren’t stored in local cache and are always fetched from main memory.
Why is volatile needed?
The volatile field is needed to make sure that multiple threads always see the newest value, even when the cache system or compiler optimizations are at work. Reading from a volatile variable always returns the latest written value from this variable.
Can a variable be both static and volatile?
static volatile: Even if the static variables are shared variables, but in different thread there can be different values for a static variable in the local cache of a thread. To make it consistent for all threads, just declare it as static volatile . So each time it will fetch from main memory.