Complex C declaration

Question

I was just going through some code on the Internet and found this:

float * (*(*foo())[SIZE][SIZE])()

How do I read this declaration? Is the

Answer 1

This document gaves me the best clue about how to easily ready any C declaration :

http://c-faq.com/decl/spiral.anderson.html

There are three simple steps to follow:

• Starting with the unknown element, move in a spiral/clockwise direction; when ecountering the following elements replace them with the corresponding english statements:

  • [X] or [] => Array X size of ... or Array undefined size of ...

  • (type1, type2) => function passing type1 and type2 returning ...

  • * => pointer(s) to ...

• Keep doing this in a spiral/clockwise direction until all tokens have been covered.

• Always resolve anything in parenthesis first!

Example :

             +-------+
             | +-+   |
             | ^ |   |
        char *str[10];
         ^   ^   |   |
         |   +---+   |
         +-----------+

Question we ask ourselves: What is str?

``str is an...

- We move in a spiral clockwise direction starting with `str' and the first character we see is a `[' so, that means we have an array, so...
  ``str is an array 10 of...

- Continue in a spiral clockwise direction, and the next thing we encounter is the `*' so, that means we have pointers, so...
  ``str is an array 10 of pointers to...

- Continue in a spiral direction and we see the end of the line (the `;'), so keep going and we get to the type `char', so...
``str is an array 10 of pointers to char''

We have now ``visited'' every token; therefore we are done!