bfd: Memory Usage

 
 2.4 Memory Usage
 ================
 
 BFD keeps all of its internal structures in obstacks.  There is one
 obstack per open BFD file, into which the current state is stored.  When
 a BFD is closed, the obstack is deleted, and so everything which has
 been allocated by BFD for the closing file is thrown away.
 
    BFD does not free anything created by an application, but pointers
 into 'bfd' structures become invalid on a 'bfd_close'; for example,
 after a 'bfd_close' the vector passed to 'bfd_canonicalize_symtab' is
 still around, since it has been allocated by the application, but the
 data that it pointed to are lost.
 
    The general rule is to not close a BFD until all operations dependent
 upon data from the BFD have been completed, or all the data from within
 the file has been copied.  To help with the management of memory, there
 is a function ('bfd_alloc_size') which returns the number of bytes in
 obstacks associated with the supplied BFD. This could be used to select
 the greediest open BFD, close it to reclaim the memory, perform some
 operation and reopen the BFD again, to get a fresh copy of the data
 structures.