How to work with structures in functions.

Hi All,

My question is how You guys prefer to call structure body from function (in embedded systems)?

Code:

---

Ex1.

    STR NewStr;
    .
    .
    fun1(&NewStr)
    .
    .

void fun1(STR *Ptr)
{
    .
    .
    Ptr->some_variable;
    .
    .
}


Ex2.

    STR NewStr;
    .
    .
    fun1()
    .
    .

void fun1()
{
    .
    .
    Ptr.some_variable;
    .
    .
}

---

What's the different in :
- address stuff
- speed

Passing a pointer to a structure usually means less overhead (memory) than passing the entire structure itself. Also, if you don't pass a pointer to it, you can't make changes to it that keep once the function has returned.


Quzah.

Quote:

---

Originally Posted by quzah

Passing a pointer to a structure usually means less overhead (memory) than passing the entire structure itself. Also, if you don't pass a pointer to it, you can't make changes to it that keep once the function has returned.


Quzah.

---

Hi Quazah,

And what about stuff like that:

Code:

---

Ex1.

    STR NewStr;
    .
    .
    fun1(&NewStr)
    .
    .

void fun1(STR *Ptr)
{
    .
    .
    Ptr->some_variable;
    .
    .
}


Ex2.

    STR NewStr;
    .
    .
    fun1()
    .
    .

void fun1()
{
    STR *Ptr = NewStr;
    .
    Ptr->some_variable;
    .
    .
}

(STR_SPORT_COMMS_DATA *) &GsmData

Ex3.

    STR NewStr;
    .
    .
    fun1()
    .
    .

void fun1()
{
    STR *Ptr = (STR *) &NewStr;
    .
    Ptr->some_variable;
    .
    .
}

---

> My question is how You guys prefer to call structure body from function (in embedded systems)?
Like this
fun1(&NewStr);

> What's the different in :
>- address stuff
>- speed
None of any significance which is worth polluting the code with vast numbers of global variables.
In addition to being a very minimal difference, it's also going to vary depending on your compiler settings, compiler and chosen machine.