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(bfd.info)Targets

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Targets
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   *Description*
Each port of BFD to a different machine requries the creation of a
target back end. All the back end provides to the root part of BFD is a
structure containing pointers to functions which perform certain low
level operations on files. BFD translates the applications's requests
through a pointer into calls to the back end routines.

   When a file is opened with `bfd_openr', its format and target are
unknown. BFD uses various mechanisms to determine how to interpret the
file. The operations performed are:

   * Create a BFD by calling the internal routine `_bfd_new_bfd', then
     call `bfd_find_target' with the target string supplied to
     `bfd_openr' and the new BFD pointer.

   * If a null target string was provided to `bfd_find_target', look up
     the environment variable `GNUTARGET' and use that as the target
     string.

   * If the target string is still `NULL', or the target string is
     `default', then use the first item in the target vector as the
     target type, and set `target_defaulted' in the BFD to cause
     `bfd_check_format' to loop through all the targets.  Note:
     bfd_target.  Note: Formats.

   * Otherwise, inspect the elements in the target vector one by one,
     until a match on target name is found. When found, use it.

   * Otherwise return the error `bfd_error_invalid_target' to
     `bfd_openr'.

   * `bfd_openr' attempts to open the file using `bfd_open_file', and
     returns the BFD.
   Once the BFD has been opened and the target selected, the file
format may be determined. This is done by calling `bfd_check_format' on
the BFD with a suggested format.  If `target_defaulted' has been set,
each possible target type is tried to see if it recognizes the
specified format.  `bfd_check_format' returns `true' when the caller
guesses right.

bfd_target