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What do you mean by volatile variable?
A volatile variable is a variable that is marked or cast with the keyword “volatile” so that it is established that the variable can be changed by some outside factor, such as the operating system or other software.
When should I use volatile in C?
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.
What is volatile variable in C where it is used?
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 does it mean to read a volatile variable?
It simply forces the compiler to explicitly read a variable whose type is volatile from the variable’s storage location (wherever that may be) rather than assuming that some previously read value in a register for example remains valid.
When to use the keyword volatile in a program?
volatile is a keyword known as a variable qualifier, it is usually used before the datatype of a variable, to modify the way in which the compiler and subsequent program treat the variable. Declaring a variable volatile is a directive to the compiler.
What does C volatile tell the compiler about a variable?
In C volatile just tells the compiler – “You don’t have enough knowledge to assume the value of this variable hasn’t changed”. There is no “section” eg BSS, CSS for it. Consider it a flag to the compiler to prevent certain types of optimisations.
What does declaring volatile do on an Arduino?
Declaring a variable volatile is a directive to the compiler. The compiler is software which translates your C/C++ code into the machine code, which are the real instructions for the Atmega chip in the Arduino.