>> Here are two alternative approaches [...]
>> 1. C99 initializers:
>>
>> config_found(self, whatever, (const struct cfargs *){
>> .search = ...,
>> .locators = ...,
>> })
That's not how C99 compound literals work. That creates an anonymous
const struct cfargs * (ie, a pointer object) but then tries to
initialize it as if it instead were the struct it points to. What you
probably want is more like
config_found(self,whatever,&(const struct cfargs){
...
});
but you have to be aware that the anonymous const struct cfargs "has
automatic storage duration associated with the enclosing block"; it
goes away once the block exits. Provided nobody saves pointers to the
struct cfargs or any of its components, this is fine, but I haven't
read the relevant code, so I don't know whether that's so.
There *is* an example (6.5.2.5 [#11]) that applies & to a compound
literal of struct type
[#11] EXAMPLE 3 Initializers with designations can be
combined with compound literals. Structure objects created
using compound literals can be passed to functions without
depending on member order:
drawline((struct point){.x=1, .y=1},
(struct point){.x=3, .y=4});
Or, if drawline instead expected pointers to struct point:
drawline(&(struct point){.x=1, .y=1},
&(struct point){.x=3, .y=4});
so I'm reasonably sure that has to work in C99.
If you want it to have static storage duration, I know of no way to do
that in C short of declaring a variable. It can be done in gcc with a
statement expression
config_found(..., ({ static const struct cfargs foo = { ... }; &foo;
}));
but I don't know how widely supported that particular extension is, and
I seem to recall seeing it said in some form that depending on gcc-only
features was frowned upon. However, I see little reason to do the
statement expression rather than
{ static const struct cfargs foo = { ... };
config_found(..., &foo);
}
/~\ The ASCII Mouse
\ / Ribbon Campaign
X Against HTML [email protected]
/ \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
