Code:
// This code works fine.// Did you call the function and step into it?
// If you never call the function, then the compiler won't bother
// putting any if there.
void Initialize_variables(void){static int number[3] = {1,2,3}; volatile int a; int i; for (i = 0 ;i < 3 ;++i) a = number[i];}"unsigned char number[3] = {1,2,3};
(without any code), then it fills below
the stack. "Which again is 100% correct. Typically, the stack is placed at the top of ram and grows down.
You can control the stack placement in the prm file.
"If I put a bunch of the arrays
into the code, then the arrays will bump
into the machine registers, giving me a
read error."
I don't remember what chip you are using. Either you've run out of memory, you used tiny model or we need to adjust your prm file. Post your prm file please.
Now the meaning of static. unfortunately the meaning of the key word static in C and C++ changes depending on how you use it. One thing very different from asm language is the concept of scoping.
variables and other items have an attribute referred to as scope, and it means who can "see" the variable.
There are three basic scopes: program, file and function.
As you know variables defined in a function can only be seen with in that function. This is function scope. Normally variable defined outside of a function have program scope, meaning and file that is linked in could see it as well as all the code in the file where it is declared.
If you declare a variable outside of a function static, that limits it's scope to only that file.
This is done to make variable private to that file.
The second meaning of static is within a function. Normally variables declared in a function are "automatic" this means they are created on the stack and go away when you leave the function.
When you declare a variable static in a function, it is no longer on the stack and is placed in ram or rom and retains it's value across function calls. However, it's scope is still for that function only.
You can however return a pointer to it so other code could see it.
I don't remember what chip you are using. Either you've run out of memory, you used tiny model or we need to adjust your prm file. Post your prm file please.
Now the meaning of static. unfortunately the meaning of the key word static in C and C++ changes depending on how you use it. One thing very different from asm language is the concept of scoping.
variables and other items have an attribute referred to as scope, and it means who can "see" the variable.
There are three basic scopes: program, file and function.
As you know variables defined in a function can only be seen with in that function. This is function scope. Normally variable defined outside of a function have program scope, meaning and file that is linked in could see it as well as all the code in the file where it is declared.
If you declare a variable outside of a function static, that limits it's scope to only that file.
This is done to make variable private to that file.
Code:
// The first meaning of static - limiting scope.static int a; // only code in this file can see 'a'int b; // any file linked into this program and see b.void (void){ // example of funcction scope. int c; // only code in this function and see 'c'}The second meaning of static is within a function. Normally variables declared in a function are "automatic" this means they are created on the stack and go away when you leave the function.
When you declare a variable static in a function, it is no longer on the stack and is placed in ram or rom and retains it's value across function calls. However, it's scope is still for that function only.
You can however return a pointer to it so other code could see it.
Code:
int* f(void){ int a=0; // created on the static. goes away when I leave this function. static int b=0; // created in ram - keeps it's value. a = 1; // The next time I call the function, a will be 0
b = 1; // b will still be 1.
return &b; // ok - lets the caller see b. return &a; // error - this would be a terrible mistake
// and will result in a crash or other odd bugs.
(you wouldn't really have two returns, just for illustration)
}
