CODEWITHSUNDEEP
cfunction-pointers
arocon
arocon

Reputation: 77

What is the explanation of the code?

Could anybody tell me what is the following code? Is it function declaration or statement? Is it valid code?

static void (*const handle_screens[NO_OF_SCREENS]) (void) =
    { status_screens, settings_screens, access_screens, configuration_screens,
      history_screens };

Upvotes: 4

Views: 168

Answers (3)

user470379
user470379

Reputation: 4879

When all else fails, and you're not 100% sure what a declaration is declaring, check out the cdecl utility. It's a Linux utility, but somebody's also created a web interface for it at cdecl.org. Pick a random number to insert for the NO_OF_SCREENS #define and you get:

> static void (*const handle_screens[1]) (void);

declare handle_screens as static array 1 of const pointer to function (void) returning void

Link to result.

Upvotes: 6

JUST MY correct OPINION
JUST MY correct OPINION

Reputation: 36107

There's a common rule (which I just refreshed my memory on) covering how to decode C declarations and definitions. Following the instructions on that link your declaration is: handle_screens is a static array with NO_OF_SCREENS entries of const pointers to functions without arguments returning void.

This array is being initialized with five functions so I'd bet that NO_OF_SCREENS is 5, personally. This means that EnabrenTane is correct in saying that the function definitions are void foo(void).

Upvotes: 1

EnabrenTane
EnabrenTane

Reputation: 7466

its a constant array of function pointers that of signature void foo(void)

Those are the easy ones. Google C Complex Declaration for the exciting ones.

Upvotes: 9

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