On Fri, 08 Jul 2011 10:49:08 +0100, Walter Bright
<[email protected]> wrote:
On 7/8/2011 2:26 AM, Regan Heath wrote:
Why can't we have the
compiler call it automatically whenever we pass a string, or char[] to
an extern
"C" function, where the parameter is defined as char*?
Because char* in C does not necessarily mean "zero terminated string".
Sure, but in many (most?) cases it does. And in those cases where it
doesn't you could argue ubyte* or byte* should have been used in the D
extern "C" declaration instead. Plus, in those cases, worst case
scenario, D passes an extra \0 byte to those functions which either ignore
it because they were also passed a length, or expect a fixed sized
structure, or .. I don't know what as I can't imagine another case where
char* would be used without it being a "zero terminated string", or
passing/knowing the length ahead of time.
D is already allocating an extra \0 byte for string constants right? And,
I assume, toStringz is already clever enough to detect cases where there
is already a \0 in the correct position, or utilises the existing
preallocated space remaining in a dynamic array, making it almost a
no-op. The only case it actually does any work is a dynamic or static
array which is full. In the former case the array is resized, and I'm not
sure about the latter but I suspect it's more expensive. So, it seems the
cost of this is very low.
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