about option_t

about option_t

[cyx_mail]

typedef struct {
	char	*name;		/* name of the option */
	enum opt_type type;
	void	*addr;
	char	*description;
	unsigned int flags;
	void	*addr2;
	int	upper_limit;
	int	lower_limit;
	const char *source;
	short int priority;
	short int winner;
} option_t;

Which piece of code call the void *addr. some plugins uses this pointer to call functions when the plugin loads. BTW, what is the exactly meaning of each value of enum opt_type struct? Thanks a lot!

2008-05-05 

Re: about option_t

[James Cameron]

On Mon, May 05, 2008 at 03:34:29PM +0800, cyx_mail@foxmail.com wrote:
> Which piece of code call the void *addr. some plugins uses this
> pointer to call functions when the plugin loads. BTW, what is the
> exactly meaning of each value of enum opt_type struct? Thanks a lot!

Not an interesting question, sorry.  Refer to the PPP source.  It is
truly fascinating and well coded.  Explore references to the option_t
typedef.  Take particular note of ->addr and where o_bool appears in the
source.  It is amazing.  Truly, amazing.  Use a capable editor and cross
referencing tool.  I use emacs with etags, but you might find something
else more appropriate.

-- 
James Cameron

Re: about option_t

[James Carlson]

cyx_mail@foxmail.com writes:
> Which piece of code call the void *addr.

'addr' is a type-dependent value.  It's not necessarily called as a
function -- that only happens if the type is o_special,
o_special_noarg, or o_wild.

> some plugins uses this pointer to call functions when the plugin loads. BTW, what is the exactly meaning of each value of enum opt_type struct? Thanks a lot!

The values should be relatively self-explanatory, if you read the code
in options.c or examine any of the code that uses the options.

  o_special_noarg - option is processed by a function call and
  consumes no other arguments.

  o_special - option processed by function call and consumes one more
  argument.

  o_bool - option address is a 'bool' to be set to the lower 8 bits of
  'flags'.  If 'addr2' is set, use the OPT_A2{COPY,CLR,CLRB,OR) to
  determine what is done to that value.

  o_int - parse an integer, offset by low 8 bits of 'flags', and store
  in 'addr'.

  o_wild - special self-identifying option (no keyword; parsed by
  appearance).  Used only for IPv4 addresses, device name, and tty
  speed.

-- 
James Carlson         42.703N 71.076W         <carlsonj@workingcode.com>

Re: Re: about option_t

[cyx_mail]

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thanks for you help!


2008-05-05 






·¢¼þÈË£º James Carlson 
·¢ËÍʱ¼ä£º 2008-05-05  19:41:21 
ÊÕ¼þÈË£º cyx_mail@foxmail.com 
³­ËÍ£º linux-ppp 
Ö÷Ì⣺ Re: about option_t 
 
cyx_mail@foxmail.com writes:
> Which piece of code call the void *addr.
'addr' is a type-dependent value.  It's not necessarily called as a
function -- that only happens if the type is o_special,
o_special_noarg, or o_wild.
> some plugins uses this pointer to call functions when the plugin loads. BTW, what is the exactly meaning of each value of enum opt_type struct? Thanks a lot!
The values should be relatively self-explanatory, if you read the code
in options.c or examine any of the code that uses the options.
  o_special_noarg - option is processed by a function call and
  consumes no other arguments.
  o_special - option processed by function call and consumes one more
  argument.
  o_bool - option address is a 'bool' to be set to the lower 8 bits of
  'flags'.  If 'addr2' is set, use the OPT_A2{COPY,CLR,CLRB,OR) to
  determine what is done to that value.
  o_int - parse an integer, offset by low 8 bits of 'flags', and store
  in 'addr'.
  o_wild - special self-identifying option (no keyword; parsed by
  appearance).  Used only for IPv4 addresses, device name, and tty
  speed.
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