How to solve expression must have a constant value error in IAR?

Question

I get the compile error: "expression must have a constant value", even though size is a constant. where is my fault ı can't find it??

 void foo(int n)
    {
    int x[n];
    int i = 5;
    if (i == 0)
    i--;
    x[i] = 5; //OK, since i is 4
    }

You should remove the `c++` tag because you mentioned that you're using C89. — SurvivalMachine, Dec 30 '19 at 14:03

SurvivalMachine · Answer 1 · 2019-12-30T14:01:07.943

0

C89 doesn't have variable length arrays, so

this line is wrong:

int x[n];

It depends on the function parameter n which is not a compile-time constant.

You could replace the raw array with a malloc:

int* x = malloc( n * sizeof( int ) );

edited Dec 30 '19 at 14:01

answered Dec 30 '19 at 13:42

SurvivalMachine

It's also specific to IAR compiler running in C89 dialect mode (or with VLA not allowed). – KamilCuk Dec 30 '19 at 13:51
ı try to compile this code in IAR WORKBENCH for static analysis . ıt support C89 – Serapmirage Dec 30 '19 at 13:53
@Serapmirage if this solves your issue, you should accept the Answer so others can find it more easily. – SurvivalMachine Dec 31 '19 at 06:32

1 Answers1