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@section File caching

The file caching mechanism is embedded within BFD and allows

the application to open as many BFDs as it wants without

regard to the underlying operating system's file descriptor

limit (often as low as 20 open files).  The module in

@code{cache.c} maintains a least recently used list of

@code{BFD_CACHE_MAX_OPEN} files, and exports the name

@code{bfd_cache_lookup}, which runs around and makes sure that

the required BFD is open. If not, then it chooses a file to

close, closes it and opens the one wanted, returning its file

handle.

@subsection Caching functions

@findex bfd_cache_init

@subsubsection @code{bfd_cache_init}

@strong{Synopsis}

@example

bfd_boolean bfd_cache_init (bfd *abfd);

@end example

@strong{Description}@*

Add a newly opened BFD to the cache.

@findex bfd_cache_close

@subsubsection @code{bfd_cache_close}

@strong{Synopsis}

@example

bfd_boolean bfd_cache_close (bfd *abfd);

@end example

@strong{Description}@*

Remove the BFD @var{abfd} from the cache. If the attached file is open,

then close it too.

@strong{Returns}@*

@code{FALSE} is returned if closing the file fails, @code{TRUE} is

returned if all is well.

@findex bfd_cache_close_all

@subsubsection @code{bfd_cache_close_all}

@strong{Synopsis}

@example

bfd_boolean bfd_cache_close_all (void);

@end example

@strong{Description}@*

Remove all BFDs from the cache. If the attached file is open,

then close it too.

@strong{Returns}@*

@code{FALSE} is returned if closing one of the file fails, @code{TRUE} is

returned if all is well.

@findex bfd_open_file

@subsubsection @code{bfd_open_file}

@strong{Synopsis}

@example

FILE* bfd_open_file (bfd *abfd);

@end example

@strong{Description}@*

Call the OS to open a file for @var{abfd}.  Return the @code{FILE *}

(possibly @code{NULL}) that results from this operation.  Set up the

BFD so that future accesses know the file is open. If the @code{FILE *}

returned is @code{NULL}, then it won't have been put in the

cache, so it won't have to be removed from it.