On 01/17/2011 05:56 PM, Jonathan Wakely wrote:
On 17 January 2011 23:04, tom fogal wrote:
I have a function with this prototype:
void to_3d(hsize_t index, const hsize_t dims[3], hsize_t outdex[3]);
The effect of the function is to store appropriate values in the
"outdex" array. It does not read or write global memory.
I would like to mark this as __attribute__((const)), but it doesn't
quite fit the definition, as it's a void function. Obviously I can't
just change it to make `outdex' the return value, since outdex is an
array.
Isn't outdex actually a pointer? That's another reason the function
can't be marked const.
It's a pointer, but the pointer is caller-provided, so I would think the
compiler could make a reasonable assumption that it "knows" the only
memory locations the called function is going to be able to modify if it
is marked 'const'.
--
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
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