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IainIreland

You aren't allowed to goto a label in a different function.

From the C standard:

> The identifier in a goto statement shall name a label located somewhere in the enclosing function.

`Shall` is a term of art here:

> If a "shall" or "shall not" requirement that appears outside of a constraint is violated, the behavior is undefined.

(Sections 6.8.6.1.1 and 4.2, respectively: http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf)

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It's undefined in the C standard. That doesn't mean its insecure or undefined as seen from the machine code. nothin is hilding you back to do your own code generation and clearly define this behaviour.

They weren't doing their own code-generation, BEAM/C treated C as the target language, and then relied on a standard C compiler. From the article:

> it is undefined behavior even in GCC. It happened to work with GCC on Sparc, but not on GCC for X86.

Appreciated.

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