Next: , Previous: , Up: BFD Front End   [Contents][Index]

2.16 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 cache.c maintains a least recently used list of bfd_cache_max_open files, and exports the name 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.

2.16.1 Caching functions

2.16.1.1 bfd_cache_init

Function: bool bfd_cache_init (bfd *abfd);

Add a newly opened BFD to the cache.

2.16.1.2 bfd_cache_close

Function: bool bfd_cache_close (bfd *abfd);

Remove the BFD abfd from the cache. If the attached file is open, then close it too.

FALSE is returned if closing the file fails, TRUE is returned if all is well.

2.16.1.3 bfd_cache_close_all

Function: bool bfd_cache_close_all (void);

Remove all BFDs from the cache. If the attached file is open, then close it too. Note - despite its name this function will close a BFD even if it is not marked as being cacheable, ie even if bfd_get_cacheable() returns false.

FALSE is returned if closing one of the file fails, TRUE is returned if all is well.

2.16.1.4 bfd_cache_set_uncloseable

Function: bool bfd_cache_set_uncloseable (bfd *abfd, bool value, bool *old);

Internal function to mark ABFD as either closeable or not. This is used by bfd_check_format_matches to avoid races where bfd_cache_close_all is called in another thread. VALUE is true to mark the BFD as temporarily uncloseable by the cache; false to mark it as closeable once again. OLD, if non-NULL, is set to the previous value of the flag. Returns false on error, true on success.

2.16.1.5 bfd_cache_size

Function: unsigned bfd_cache_size (void);

Return the number of open files in the cache.

2.16.1.6 bfd_open_file

Function: FILE* bfd_open_file (bfd *abfd);

Call the OS to open a file for abfd. Return the FILE * (possibly NULL) that results from this operation. Set up the BFD so that future accesses know the file is open. If the FILE * returned is NULL, then it won’t have been put in the cache, so it won’t have to be removed from it.

Next: Linker Functions, Previous: Implementation details, Up: BFD Front End   [Contents][Index]