This discussion has been locked.

You can no longer post new replies to this discussion. If you have a question you can start a new discussion

method to avoid global variables

I want to know method, How to avoid global variable in c microcontroller programing? or method to make global variable invisible.
Is there any perticular functions in built in c library?, that could be supportive to avoid global variables or hide global variables.

Parents

0 erik malund over 20 years ago in reply to erik malund

I just recall an incident.
I worked bnriefly at a place thet had the "under penalty of severe bodily harm, do not use any global variables" rule.
I had to make a variable accessible to 2 functions (b and y) and was told to do it this way:

void main (void)
{
struct st
...
unsigned char ch
...


funca (*st)

funcv( *st)

...
}

funca (*structure)
{
...
funcb (*structure)
...
}

funcb (*structure)
{
....
ralph = st.ch
...
}

funcv (*structure)
{
...
funcw (*structure)
...
}

funcw (*structure)
{
...
funcx (*structure)
...
}


funcx (*structure)
{
...
funcy (*structure)
...
}

funcy (*structure)
{
....
st.ch = george
...
}

with EVERY function that carries the *function able to modify ch where is the gain.

this should look like


unsigned char ch
void main (void)
{

funca ()

funcv()

...
}

funca ()
{
...
funcb ()
...
}

funcb ()
{
....
ralph = ch
...
}

funcv ()
{
...
funcw ()
...
}

funcw ()
{
...
funcx ()
...
}


funcx ()
{
...
funcy ()
...
}

funcy ()
{
....
ch = george
...
}

and run 47 times faster

Erik

Reply

0 erik malund over 20 years ago in reply to erik malund

void main (void)
{
struct st
...
unsigned char ch
...


funca (*st)

funcv( *st)

...
}

funca (*structure)
{
...
funcb (*structure)
...
}

funcb (*structure)
{
....
ralph = st.ch
...
}

funcv (*structure)
{
...
funcw (*structure)
...
}

funcw (*structure)
{
...
funcx (*structure)
...
}


funcx (*structure)
{
...
funcy (*structure)
...
}

funcy (*structure)
{
....
st.ch = george
...
}

with EVERY function that carries the *function able to modify ch where is the gain.

this should look like


unsigned char ch
void main (void)
{

funca ()

funcv()

...
}

funca ()
{
...
funcb ()
...
}

funcb ()
{
....
ralph = ch
...
}

funcv ()
{
...
funcw ()
...
}

funcw ()
{
...
funcx ()
...
}


funcx ()
{
...
funcy ()
...
}

funcy ()
{
....
ch = george
...
}

and run 47 times faster

Erik

Children

No data