Fibonacci Number in Clang Block

fibonacci.c

/* copyright (c) 2020 Michael chen.
   Licensed under Apache 2.0 */
#include <stdio.h>
#include <Block.h>


typedef unsigned (^uint_block)(void);
typedef uint_block (^uint_closure)(void);

int main(void)
{
    uint_closure fib_generator = ^(void) {
        __block unsigned a = 0;
        __block unsigned b = 1;

        return Block_copy(^(void) {
            unsigned out = a;
            a = b;
            b = a + out;
            return out;
        });
    };

    uint_block fib = fib_generator();

    {
        size_t i;
        for (i = 0; i < 12; ++i)
             printf("%u\n", fib());
    }

    return 0;
}

You need both clang and blocksruntime on non-Apple platforms.

Compile blocksruntime into a static library; later, compile the program:

$ clang -o fibonacci fibonacci.c path/to/libBlocksRuntime.a -I path/to/BlocksRuntime -fblocks