iterator macros and requiring gcc >= 3.0 and -std=c9x

[Marcus Brinkmann]

Hi,

I would like some iterator macros for the driver plugin code in the console
client.  I have written this so far:

#define driver_iterate(drv)                                             \
  for (mutex_lock (&driver_list_lock), drv = &driver_list[0];           \
       drv <= &driver_list[driver_list_len - 1];                        \
       drv++, (drv == &driver_list[driver_list_len - 1]                 \
               ? mutex_unlock (&driver_list_lock) : 0)

Which can be used like this:

   driver_t driver;
   driver_iterate (driver)
     {
       printf ("%s\n", driver->ops->name);
     }

Neal pointed out that C99 allows to define variables in statements, so the
following would work:

#define driver_iterate                                                    \
  for (mutex_lock (&driver_list_lock), driver_t driver = &driver_list[0]; \
       driver <= &driver_list[driver_list_len - 1];                       \
       driver++, (driver == &driver_list[driver_list_len - 1]             \
                  ? mutex_unlock (&driver_list_lock) : 0)

Which can be used like this:

   driver_iterate
     {
       printf ("%s\n", driver->ops->name);
     }

eliminating the need for a user-defined variable.  It's no big deal, but if
you prefer the second version, we need to use -std=c9x in our CFLAGS.  What
do you think?

Thanks,
Marcus

-- 
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Marcus Brinkmann              The Hurd http://www.gnu.org/software/hurd/
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http://www.marcus-brinkmann.de/