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- Subject: Re: [ANN] Lua 5.2.0 (rc4) now available
- From: "Dimiter \"malkia\" Stanev" <malkia@...>
- Date: Thu, 01 Dec 2011 21:29:28 -0800
That's what I thought, until I stumbled onto this article:
The problem arises when varargs are used, so lua might (haven't checked)
not be hitting the issue.
Take this example, from the article:
The 0 at the end is supposed to be NULL.
In 32-bit code everything is okay, but in 64-bit code, 0 is still
32-bits (for certain compilers), and the function instead of receiving
NULL receives something else.
It's just a pitfall to be aware, in other contexts I guess one can
freely replace NULL with 0 (until someone else discover problem with that).
On 12/1/11 1:51 AM, Miles Bader wrote:
Enrico Colombini<firstname.lastname@example.org> writes:
"0" should be perfectly acceptable in a pointer context; this sounds
like a bug with the C compiler...
That's in C++.
It's acceptable in both C and C++.
In C, if I remember correctly, there is no automatic conversion and
the integer/pointer types could be incompatible on some hardware.
You remember incorrectly. Both C and C++ will automatically do the
implicit conversion of a "0" in the source code to the appropriate
pointer type in a pointer context.
Remember, we're talking about "0" in the source code, not a run-time
value of zero; a NULL pointer may indeed have a non-zero value at