BFD io function pointers

[SammyG <sammygamuel at gmail dot com>]

Hi all.

Where in the code are the function pointers in bfd_iovec actually 
assigned functions? And where are the function definitions for these 
functions?

/* Extracted from bfdio.c.  */
struct bfd_iovec
{
  /* To avoid problems with macros, a "b" rather than "f"
     prefix is prepended to each method name.  */
  /* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching
     bytes starting at PTR.  Return the number of bytes actually
     transfered (a read past end-of-file returns less than NBYTES),
     or -1 (setting <<bfd_error>>) if an error occurs. */
  file_ptr (*bread) (struct bfd *abfd, void *ptr, file_ptr nbytes);
  file_ptr (*bwrite) (struct bfd *abfd, const void *ptr,
                      file_ptr nbytes);
  /* Return the current IOSTREAM file offset, or -1 (setting <<bfd_error>>
     if an error occurs.  */
  file_ptr (*btell) (struct bfd *abfd);
  /* For the following, on successful completion a value of 0 is returned.
     Otherwise, a value of -1 is returned (and <<bfd_error>> is set).  */
  int (*bseek) (struct bfd *abfd, file_ptr offset, int whence);
  int (*bclose) (struct bfd *abfd);
  int (*bflush) (struct bfd *abfd);
  int (*bstat) (struct bfd *abfd, struct stat *sb);
  /* Mmap a part of the files. ADDR, LEN, PROT, FLAGS and OFFSET are 
the usual
     mmap parameter, except that LEN and OFFSET do not need to be page
     aligned.  Returns (void *)-1 on failure, mmapped address on success.
     Also write in MAP_ADDR the address of the page aligned buffer and in
     MAP_LEN the size mapped (a page multiple).  Use unmap with 
MAP_ADDR and
     MAP_LEN to unmap.  */
  void *(*bmmap) (struct bfd *abfd, void *addr, bfd_size_type len,
                  int prot, int flags, file_ptr offset,
                  void **map_addr, bfd_size_type *map_len);
};