Insuring a function is only called from a macro

[holysmoke]

Hi all,
I have a function

void actualfunction(unsigned int t, unsigned int lineno)
{
....
}

I want that it is called only from a macro I wrote for it (I don't
want to use a wrapper function) like,

#define FUNCTION(a) actualfunction((a), __LINE__)

How to do I insure that actualfunction is only called as FUNCTION?
One thing I could do is, call another function that sets a global
variable and then test that variable in 'actualfunction'.

#define FUNCTION(a) setTest(); \
actualfunction((a), __LINE__); \
void setTest(void)
{
static unsigned char test;
test = 0xFF;
}

void actualfunction(unsigned int t, unsigned int lineno)
{
assert(test == 0xFF);
test = 0x00;

....
}
BTW I'm ok to ignore the case where some calls setTest and then
actualfunction directly but this is a run time check, is a compile
time check posssible?




Would appreciate any pointers. Thanks!

 

[Richard Tobin]

I want that it is called only from a macro I wrote for it (I don't
want to use a wrapper function) like,

You can't. Anything the macro expands to, the user could just
write themselves.

The simplest solution is to give the function an obscure name that
makes it clear it shouldn't be used, like xxx_function_internal, or
function_calling_me_directly_invalidates_warranty. And document
the fact that it shouldn't be used.

-- Richard