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SubjectRe: [RFC v2 2/7] tables.h: add linker table support
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On 02/19/2016 05:45 AM, Luis R. Rodriguez wrote:
> +/**
> + * LINKTABLE_RUN_ERR - run each linker table entry func and return error if any
> + *
> + * @tbl: linker table
> + * @func: structure name for the function name we want to call.
> + * @args...: arguments to pass to func
> + *
> + * Example usage:
> + *
> + * unsigned int err = LINKTABLE_RUN_ERR(frobnicator_fns, some_run,);
> + */
> +#define LINKTABLE_RUN_ERR(tbl, func, args...) \
> +({ \
> + size_t i; \
> + int err = 0; \
> + for (i = 0; !err && i < LINKTABLE_SIZE(tbl); i++) \
> + err = (tbl[i]).func (args); \
> + err; \
> +})

This is wrong and pointless. As written it returns the error code of
the last instance.

What I suggested for this macro was that we ought to exit the loop on error.

Furthermore:

1. Using an advancing pointer would make more sense than a counter.
2. .func doesn't make any sense -- it ought to be "func"; otherwise you
can't call into either a table containing pure function pointers,
nor into a field of table *pointed to* by the table; which is
likely to be quite common.

So the idea is to use something like:

/* Array of function pointers */
LINKTABLE_RUN_ALL(frobnicator_fns, , arg1, arg2);

/* Array of structures */
LINKTABLE_RUN_ALL(frobnicator_fns, .some_run, arg1, arg2);

/* Array of structure pointers */
LINKTABLE_RUN_ALL(frobnicator_fns, ->some_run, arg1, arg2);

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