Thread: memory structure

Originally Posted by Kittu20

sorry but i don't find in paragraph that show where address of function store in which area

imagine we have code where does foo() and fun will store and in which reason of memory

Code:

 #include<stdio.h>

void foo()
{
    printf("Welcome \n");
}


static void fun ()
{
    printf("Hello \n");
}
int main ()
{
    foo();
    fun ();
    return 0;
}

static here have a different meaning. For functions it means the identifier fun won't be exported (the function is local to the module).

main and foo are exported (made extern).

In this example all bytes for the functions are encoded in .text section.

Why this is useful? Take a look at this:

Code:

// test1.c
#include <stdio.h>

extern void g( void );

static void f( void ) { puts( "I'm f() from test1.c" ); }

int main( void ) { f(); g(); return 0; }

Code:

// test2.c
#include <stdio.h>

static void f( void ) { puts( "I'm f() from test2.c" ); }

void g( void ) { f(); } // calls the module local f().

Code:

$ cc -O2 -c *.c
$ cc -s -o test test1.o test2.o
$ ./test
I'm f() from test1.c
I'm f() from test2.c

Different functions with the same name in different modules.

PS: The functions declarations with () are wrong, in C. Modern compilers allows it, but the correct way to declare is:

Code:

int main( void ) // void is necessary!
{
  ...
}

Otherwise, this code is C++, not C.