a compiling error just after I added one more static var!

[naughty_mark]

Hi there, long time no see~

I am using dsPIC22EP256MU814 with CCS compiler version 4.133
I just met an odd scenario and would like to ask you guys if met that before and know the answer,

The thing is, I have a .h file which keeps lots of static vars ( I know it is not a good programming habit), and just after I add one more var such as "static unsigned int16 abcde;", then the compiler bugs somewhere else (a function in other .c file) which did pass compiled before this var added in.

I did following things:
1. I tried different name to name the new var, and I am sure there is no duplicate var in this project.

2. no matter which .h file I put the declaration of that var, same compiling error.

3. Then I deleted one of unused static var in that .h file(which keep lots of static vars), and keep the new added var in. Then it passed the compile.

4. Based on 3, I doubted that it looks CCS put static vars in a particular place in RAM, and that area has some size limitation. However, even I just delete AN unsigned int16 var and add An ARRAY of unsigned int16 vars, it will pass the compile. So it looks the assumption that "size limitation" not quite right.

5. The RAM usage of my program is 33% at worst. I think static vars will be placed in RAM just can not be cleaned by micro and keep staying there, right?

Anyone who met this scenario before?
Thanks a lot
Mark

[Ttelmah]

A couple of comments:

These variables (declared outside the main code), are presumably _global_?.
As such, you don't need them to be declared as 'static', unless you require the default behaviour for these, which is to initialise them to 0.

A global variable, is always intrinsically static. A variable declared as 'static', is initialised to zero.

Except for the need for initialisation (which I must admit I'd normally implicitly initialise variables anyway), static would normally only be needed for variables local to a function.

So, for global variables:

static int16 fred;

is equivalent to

int16 fred=0;

The only other difference of a static variable, is that if using linked code modules, a static variable is not visible outside the module.

So I'd start by trying removing the static declarations, provided the variables are initialised elsewhere (avoids wasted code).

I'd guess you are hitting a limit on the actual number of static variables, rather than the memory used by them. You might try something 'silly', like using the command line compiler, with the -M option (which stops a symbol file being generated), since it could be as simple as running out of space for generating this.

You need to report it to CCS.

Best Wishes

[naughty_mark]

Thanks for your advice, Ttelmah. I will try to contact with CCS see if they know why.

[Ttelmah]

As another comment for reducing the number of variables, remember it is normally much more logical, to 'group' variables that work together. So (for example), a set of variables configuring a timer, would be much more logically arranged as:

[naughty_mark]

Thanks Ttelmah, that is a good idea.
I still hope CCS can fix those bugs, actually I found some when I did my project, really made me upset. Sometimes just a version update, then my code can not pass compile....

[Ttelmah]

A search here will find a lot about compiler updates:

General rules are.

1) CCS releases are beta at best.
2) If you are working with a particular compiler, and don't need a feature that appears in a new release, don't 'upgrade'.
3) Always keep the compiler version number used, and the compiler itself _with_ each project.

Basically, CCS have the annoying habit of making dozens of changes, and documenting just one or two. When they fix one problem, they'll often screw up dozens of other things. This is why 'old hands' here, have literally dozens of compilers and can go back to older versions.

Best Wishes