Monday, December 25, 2017

What is a c storage class

C storage class

What does a storage class got to do with the C language? Storage classes in C actually play a big role in the name declaration syntax.
         A storage class indicates the scope the variables cover and also the duration they are to remain stored – what you can call their lifetime. It also controls its linkage.                    In the C programming language, storage classes are four. Here are C’s storage classes:
               



  • Auto 
  • Register
  • Static
  • Extern



  • Auto
This is C’s default storage class for every local variable. Its storage duration is automatic and it operates within functions.

  • Register
The term register is used here because the storage class specifier prompts the compiler to put the object in question within the register in the processor. 
            As for storage, the duration here is also automatic. The uniqueness with the register storage class is that it helps identify any local variable that needs to be stored within the register as opposed to being held within RAM (Random Access Memory). This automatically means that the size of your variable cannot exceed that of the register. 
          Ordinarily that size which is meant to fit the register is only a single word; without adding something like & as there is no memory location for 
it.

  • Static 
This is the same one sometimes referred to as thread storage. Its storage is static and has internal linkage. 
              What this static storage class does is give indication to the compiler that the local variable needs to be spared as long as the program lasts. 
             This is as opposed to it being destroying it when it gets out of scope. Owing to this manner of functioning, the variables retain their exact values in between function calls.

  • Extern 
This is the same one sometimes referred to as thread storage. Its storage is static and has internal linkage. 
          What this static storage class does is give indication to the compiler that the local variable needs to be spared as long as the program lasts. 
           This is as opposed to it being destroying it when it gets out of scope. Owing to this manner of functioning, the variables retain their exact values in between function calls.
             It is simply a name denoting object, value, reference, template, function, namespace, or even type.


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