Comment by rmind

A lot C programmers prefer to keep structures within the C source file ("module"), as a poor man's encapsulation. For example:

component.h:

    struct obj;
    typedef struct obj obj_t;

    obj_t *obj_create(void);
    // .. the rest of the API

component.c:

    struct obj {
        int status;
        // .. whatever else
    };

    obj_t *
    obj_create(void)
    {
        return calloc(1, sizeof(obj_t));
    }

However, as the component grows in complexity, it often becomes necessary to separate out some of the functionality (in order to re-abstract and reduce the complexity) into a another file or files, which also operate on "struct obj". So, we move the structure into a header file under #ifdef __COMPONENT_PRIVATE (and/or component_impl.h) and sprinkle #define __COMPONENT_PRIVATE in the component source files. It's a poor man's "namespaces".

Basically, this boils down to the lack namespaces/packages/modules in C. Are you aware of any existing compiler extensions (as a precedent or work in that direction) which could provide a better solution and, perhaps, one day end up in the C standard?

P.S. And if C will ever grow such feature, I really hope it will NOT be the C++ 'namespace' (amongst many other depressing things in C++). :)