On Thursday, 2 June 2022 at 08:14:40 UTC, Mike Parker wrote:
You've initialized `str` with a string literal. No memory is
allocated for these from the GC. They're stored in the binary,
meaning they're loaded into memory from disk by the OS. So
`str.ptr` points to a static memory location that's a fixed
size, hence no extra capacity.
I didn't know that, so maybe this example proves it; the
following test code that Ali has started and I have developed:
```d
import std.range;
import std.stdio;
/* toggle array:
alias chr = char*;
auto data = [' '];/*/
alias chr = immutable(char*);
auto data = " ";//*/
void main()
{
chr[] ptrs;
data.fill(3, ptrs);
writeln;
foreach(ref ptr; ptrs)
{
" 0x".write(ptr);
}
} /* Print Out:
0: 0 1: 15 2: 31 3: 47
0x55B07E227020 0x7F2391F9F000 0x7F2391FA0000 0x7F2391FA1000
//*/
void fill(R)(ref R mostRecent,
int limit,
ref chr[] ptrs)
{
auto ptr = mostRecent.ptr;
size_t capacity, depth;
while (depth <= limit)
{
mostRecent ~= ElementType!R.init;
if(ptr != mostRecent.ptr)
{
ptrs ~= ptr;
depth.writef!"%2s: %11s"(capacity);
depth++;
}
if (mostRecent.capacity != capacity)
{
ptr = mostRecent.ptr;
capacity = mostRecent.capacity;
}
}
}
```
As for the result I got from this code: The array configured in
the heap is copied to another memory region as soon as its
capacity changes (0x5...20 >> 0x7...00). We get the same result
in array. Just add the / character to the beginning of the 4th
line to try it.
Thank you all very much for the replies; all of these open my
mind.
SDB@79
