Expected Specifier Qualifier List error inside struct

Question

I am getting the error

error: expected specifier-qualifier-list before ‘(’ token

On the line beginning with (const char)* below and I do not understand what this error means. What does it mean? (Note that there is another question on this topic, but the one answer in the other question does not explain what the error means.)

#include "stddef.h"        /* size_t */

typedef struct {
     size_t size;
     (const char)* strings[];
} STRLIST;

static STRLIST listMediaType = {
     7,
     {
         "Book",
         "Map",
         "Booklet",
         "Pamphlet",
         "Magazine",
         "Report",
         "Journal"
     }
 };

@user3386109 Yes, it did, but how can I can understand the error message. In other words why does this particular error message occur here? — Tyler Durden

user3386109 user3386109 · Accepted Answer · 2016-06-23T03:27:51

You can sort of fix the problem by removing the parentheses. That's only sort of fixing the problem because the C specification forbids the initialization of flexible array members with initializer lists. However, clang (and I assume gcc) allow it as an extension. If you compile with -Weverything, you should get a warning that you're using an extension.

As for why the parentheses are not allowed: to truly understand that you need to read section "6.7 Declarations" in the specification, which is 38 pages long. Short answer is that the compiler was expecting a declaration. A declaration starts with a variety of specifiers and qualifiers, none of which start with parentheses.

So the proper interpretation of the error message (from the compiler's point of view) is:

"I was expecting the declaration of a structure member, which should start with a specifier or qualifier, but instead you gave me a parentheses. Don't do that."

Expected Specifier Qualifier List error inside struct

2 Answers