This is part of my pending breakpoint changes.  Daniel asked to break it up into 
a few pieces; this being one of them.

I have added two new paramters to decode_line_1.  One is a reason_code field and 
the other is a silent_flag.  The reason code is a pointer to an int to store a 
reason code should the function cause an error.  At present, the reason_code is 
only set if the file or function is not found.  I would have called it 
not_found_ptr instead of reason_code_ptr but I felt this could be enhanced in 
the future to include other forms of error that could be of interest to the 
caller.  The reason code works like errno whereby the caller is expected to 
clear the field before calling and check it afterwards.  The silent_if_not_found 
flag tells the function not to issue an error message if the function is to fail 
because the function/source file is not found.

Ok to commit?

-- Jeff J.

2003-12-08  Jeff Johnston  <jjohnstn@redhat.com>

	* linespec.h (decode_line_1): Add new reason_code_ptr and
	silent_if_not_found parameters.  Add new DL1_NOT_FOUND reason
	code macro.
	* linespec.c (decode_line_1): Add new parameters.  Pass on
	new parameters to decode_variable and symtab_from_filename
	functions.
	(decode_variable): Add new reason_code_ptr and silent_if_not_found
	parameters.  Set reason code if failing because function not
	found.  Throw exception rather than calling error() if silent
	flag is set and function is not found.
	(symtab_from_filename): Add new reason_code_ptr and silent_if_not_found
	parameters.  Set reason code if failing because source file not
	found.  Throw exception rather than using error call if
	silent flag is set and source file is not found.
	* breakpoint.c: Change all callers of decode_line_1 to add default
	extra parameters for decode_line_1 calls.
	* tracepoint.c: Ditto.
	* cli/cli-cmds.c: Ditto.