Conference turris::decc

2104.0. "Needconstexpr, with extra level of indirection??" by COMICS::PULLEY () Mon Feb 24 1997 10:43

Hi Folks,

I've a customer trying to upgrade things from DEC C v1.3 to v5.3.
I've tryed a small sample of a program that compiled on v1.3, on
OpenVMS v7.1 Alpha, DEC C v5.5.

It gives the following error:-
%CC-E-NEEDCONSTEXPR, In the initializer for urec_flight_key, "unit_rec_ptr"...

I've not been able to figure if it was right to allow it in the earlier
version, or unreasonable of the compiler not to in teh current.
He's trying a workaround of changing the line it complains about to:-
long *urec_flight_key= &(unit_record.flight_key);

Thanks for any comments or suggestions,
Steve.

This is the little program:-
typedef struct
{
    long flight_key;
} unit_record_typedef;

unit_record_typedef unit_record;
unit_record_typedef *unit_rec_ptr=&unit_record;

long *urec_flight_key= &(unit_rec_ptr->flight_key);

void main (void)

{}

The difference can be explained:  the 1.3 compiler erroniously accepts the
construct and (yikes) generates incorrect code for it.  The 5.* compilers
recognize the bogus construct and issue the error... generating no code at all.

Fortunately, your workaround will make all the compilers do what the programmer
had intended in the first place.

Eric