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set_flag(+Flag, ++Value)
Succeeds if the flag Flag is successfully set to the value Value.
- Flag
- Atom.
- Value
- Atomic or compound term.
Description
   Used to set the environment flag Flag to the value Value.  The current
   value of a flag may be returned using get_flag/2.  Refer to the
   specification of get_flag/2 for details about each of the environment
   flags.
Modes and Determinism
Modules
This predicate is sensitive to its module context (tool predicate, see @/2).
Exceptions
- (4) instantiation fault 
- Flag and/or Value are not instantiated.
- (5) type error 
- Flag is neither an atom nor a variable.
- (5) type error 
- Value is not of the expected type.
- (6) out of range 
- Flag and/or Value are out of range.
- (30) trying to write a read-only flag 
- Flag is a read-only flag.
Examples
Success:
   set_flag(gc,verbose).
   set_flag(syntax_option, no_blanks).
   set_flag(syntax_option, not nl_in_quotes).
   % The following example will set a new library path
   [eclipse]: get_flag(library_path,Path),
      set_flag(library_path, ["/home/myuser/mylibs" | Path]).
   Path = ["/usr/local/ECLIPSE/lib"]
   yes.
Fail:
   set_flag(statistics, some).
Error:
   set_flag(X,a).                (Error  4)
   set_flag("a",x).              (Error  5)
   set_flag(blah, a).            (Error  6)
   set_flag(gc,fred).            (Error  6)
   set_flag(version,1).          (Error 30)
See Also
get_flag / 2, env / 0, cd / 1, compile / 1, compile / 2, dynamic / 1, pragma / 1, lib / 1