Scope of varibales in C?

Hello All,

I came to face some issues regarding the scope of variables.

Eg: String literal has a scope which is lifetime (entire program).

Where can i find such rules which are not commonly written in every book.
Plz give me a link or some document stating such all the scope rules clearly.


Regards

Let me Google that for you .

You didn't need to make a new thread for this. You did need to search the internet.

Static variable - Wikipedia, the free encyclopedia
String literal - Wikipedia, the free encyclopedia
Scope (computer science) - Wikipedia, the free encyclopedia


Quzah.

Like so

Code:

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int global;  // lifetime of program, scope everywhere
static int local;  // lifetime of program, scope is current source file
void foo ( ) {
  static int bar;  // lifetime of program, scope is  current function
  int count;  // lifetime of function, scope is  current function
  for ( count = 0 ; count < 10 ; count++ ) {
    int temp; // scope is up to the matching }
  }
}

---

For string literals, like
char *s = "this is a string";
the only thing you can be sure of is that "this is a string" has a lifetime of the program. If two source files have the same string constant, then one of them could be removed.

All other initialisation data could be stored in a variety of unspecified ways.
For example

Code:

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char msg[] = "hello";

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May be implemented as

Code:

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char msg[6];
strcpy(msg,"hello");

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or

Code:

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char msg[6]
msg[0] = 'h';
msg[1] = 'e';
// and so on

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Quote:

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Eg: String literal has a scope which is lifetime (entire program).

---

Another point you might have misunderstood.
The following code is perfectly invalid.

Code:

---

#include<stdio.h>
void foo(void);
int main(void)
{
        printf("%s",s);
        return 0;
}

void foo(void)
{
        char *s ="xyz";
}

---

You can only use a literal away from its local scope if you manage to get hold of its address.

Scope and lifetime are completely different concepts. True, lifetime is often associated with scope, but that is not always true.

The definitive answer can be found in or around section 6.2 of the standard. Here we have a link to that.

@AndrewHunter
Very nice doc shared. Thank you for this... :)

Quote:

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Originally Posted by AndrewHunter

The definitive answer can be found in or around section 6.2 of the standard. Here we have a link to that.

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