1@section File caching
2The file caching mechanism is embedded within BFD and allows
3the application to open as many BFDs as it wants without
4regard to the underlying operating system's file descriptor
5limit (often as low as 20 open files).  The module in
6@code{cache.c} maintains a least recently used list of
7@code{bfd_cache_max_open} files, and exports the name
8@code{bfd_cache_lookup}, which runs around and makes sure that
9the required BFD is open. If not, then it chooses a file to
10close, closes it and opens the one wanted, returning its file
11handle.
12
13@subsection Caching functions
14
15
16@findex bfd_cache_init
17@subsubsection @code{bfd_cache_init}
18@deftypefn {Function} bool bfd_cache_init (bfd *abfd); 
19Add a newly opened BFD to the cache.
20
21@end deftypefn
22@findex bfd_cache_close
23@subsubsection @code{bfd_cache_close}
24@deftypefn {Function} bool bfd_cache_close (bfd *abfd); 
25Remove the BFD @var{abfd} from the cache. If the attached file is open,
26then close it too.
27
28@code{FALSE} is returned if closing the file fails, @code{TRUE} is
29returned if all is well.
30
31@end deftypefn
32@findex bfd_cache_close_all
33@subsubsection @code{bfd_cache_close_all}
34@deftypefn {Function} bool bfd_cache_close_all (void); 
35Remove all BFDs from the cache. If the attached file is open,
36then close it too.  Note - despite its name this function will
37close a BFD even if it is not marked as being cacheable, ie
38even if bfd_get_cacheable() returns false.
39
40@code{FALSE} is returned if closing one of the file fails, @code{TRUE} is
41returned if all is well.
42
43@end deftypefn
44@findex bfd_cache_size
45@subsubsection @code{bfd_cache_size}
46@deftypefn {Function} unsigned bfd_cache_size (void); 
47Return the number of open files in the cache.
48
49@end deftypefn
50@findex bfd_open_file
51@subsubsection @code{bfd_open_file}
52@deftypefn {Function} FILE* bfd_open_file (bfd *abfd); 
53Call the OS to open a file for @var{abfd}.  Return the @code{FILE *}
54(possibly @code{NULL}) that results from this operation.  Set up the
55BFD so that future accesses know the file is open. If the @code{FILE *}
56returned is @code{NULL}, then it won't have been put in the
57cache, so it won't have to be removed from it.
58
59@end deftypefn
60