Question

How does the following snippet work? What is IN? Eclipse says that IN stands for ‘macro expansion’:

 UWORD32 (*get_u32)(IN UWORD8 *buffer_ptr);    /* Gets unsigned 32bit word   */
                                           /* from the buffer */

This above code is part of a struct. and is used like this.

struct my struct s;
UWORD8* buf;

s->get_u32(buf);

How does it work?

Answer 1

I would guess that IN is #defined somewhere as const:

#define IN const    // input parameters are const

get_u32 is just a function pointer – the function takes a single parameter (a pointer to a UWORD8) and returns a UWORD32.