Aix compilation error due to #define

Question

"1506-221 (S) Initializer must be a valid constant expression."

In aix during compilation of header file i am facing this issue.

In the header file the source is like

#define A(b) (a+b)

like that.

wherever this macro "A"(Ex:A(5)) is used in source it throws the above error.

can anyone help me to solve this?

Edited:

in the header file

#define A(b) (a+b)

in the source file

struct a
{
   int a;
   int b;
} ain = {10, A(10)};

like this .

What is compilation of header? Are you using precompiled headers? — Iharob Al Asimi, Feb 08 '16 at 14:05
No,I am using one header file named a.h in that i defined like that.so in the source c file whereever i used that macro it throws that error.other platforms like linux or solaris it worked ,only aix it is not working — freeworld, Feb 08 '16 at 14:07
What is `a` and `b`? There are no variables `a` and `b` in your code that can be used in the initializer list. Or otherwise, how exactly do you think it makes sense to initialize a variable to 10 plus its own uninitialized value? — Lundin, Feb 08 '16 at 14:14
@Lundin: `b` is the marco argument, thus ok. Buit `a` is missing. — too honest for this site, Feb 08 '16 at 14:17
@Olaf, after the edit you can see that `a` is one of the structure fields. The OP thinks. — Iharob Al Asimi, Feb 08 '16 at 14:18
There's no point in speculating really, this is complete nonsense code. — Lundin, Feb 08 '16 at 14:20
@iharob: Which is not know in the global namespace. I'd actually be surprised if a `struct` initialiser is allowed to reference a struct-member that way in C. — too honest for this site, Feb 08 '16 at 14:20

Iharob Al Asimi · Answer 1 · 2016-02-08T14:23:29.530

1

You can't initialize a structure with a non constant value, in this case you are using one of the structure fields I suppose but as it is your macro doesn't even know that since a isn't actually defined to be anything, try this instead

#define INIT_STRUCT(x, a, b) do {x->a = a; x->b = x->a + b} while (0);

and use it like this

struct a {int a; int b;};
INIT_STRUCT(&a, 10, 10);

NOTE: But please don't do this, instead just initialize it like this

a.a = 10;
a.b = a.a + 10;

or if you need to initialize many of these write a function instead.

edited Feb 08 '16 at 14:23

answered Feb 08 '16 at 14:16

Iharob Al Asimi

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No, don't write code like this, it is horrible, unreadable obfuscation. – Lundin Feb 08 '16 at 14:20
@freeworld: Agreeing with Lundin, you should not use such constructs. Drop that macro approach and use designated initialisers. – too honest for this site Feb 08 '16 at 14:22
@Lundin I agree, but this is what the OP wants. Still, it would be nice to leave a note telling them NOT TO DO THIS. – Iharob Al Asimi Feb 08 '16 at 14:22

Aix compilation error due to #define

1 Answers1