Why is a typedef not allowed in the inner struct?

c, gcc, struct, typedef

Solution

C does not allow a storage-class specifier (`typedef`, but also `static` or `extern`) in the declaration of a structure member. This is specified in the syntax of structures and unions declaration in 6.7.2.1p1 in C99.

/* The compiler will issue a diagnostic for this declaration */ 
struct s {    
    static int a;
};

You can compare 6.7.2.1p1 syntax with the syntax of a declaration where the declarator is not a function parameter or a structure / union member in 6.7p1 and see that in this case the storage-class specifiers are allowed.

Problem

I have a program that defines a typedef struct within an existing typedef struct, and I am wondering why I am getting a compilation error. Here is the program: ``` typedef struct Outer { typedef struct Inner { int b; }INNER; INNER inner; int a; }OUTER; int main() { OUTER obj; obj.a = 10; obj.inner.b=8; return 0; } ``` on compilation gives following error :: ``` test.c:3:5: error:expected specifier-qualifier-list before ‘typedef’ test.c: In function ‘main’: test.c:17:5: error: ‘OUTER’ has no member named ‘a’ test.c:18:5: error: ‘OUTER’ has no member named ‘inner’ ``` but, when I changed the program to ``` typedef struct Outer { struct Inner { int b; }; struct Inner inner; int a; }OUTER; int main() { OUTER obj; obj.a = 10; obj.inner.b=8; return 0; } ``` it compiles successfully. Why is typedef not allowed with inner structures?

Original source