Hi,

I think it would have been way better if the algorithms worked with output ranges, rather than output iterators. A back_inserter output range could have an unreachable sentinel. People could opt-in to no bound checking with a pointer by explicitly creating a subrange with unreachable sentinel.

There is also no one liner to create a bound-checked output iterator. And the only way to signal out-of-bounds is with an exception. I am absolutely not a fan.

But my vague recollection is that people didn't like std::ranges::copy(input_range, output_range), which is more of a naming problem IMO.

Cheers,
Lénárd

On 2 October 2022 12:32:54 BST, Marcin Jaczewski via Std-Discussion <std-discussion@lists.isocpp.org> wrote:
niedz., 2 paź 2022 o 10:35 Olaf van der Spek via Std-Discussion
<std-discussion@lists.isocpp.org> napisał(a):

Hi,

This snippet overflows the destination buffer. Is format_to too easy to misuse?
Shouldn't it requires an iterator to the end so it could avoid this issue?
It seems like a modern equivalent of fgets()

#include <format>
#include <iostream>

int main()
{
  char d[10] = {};
  std::format_to(d, "0123456789 {}", 42);
  std::cout << std::string_view(d, 10) << std::endl;
}

This is more of a problem with raw pointers than this function.
Example on https://en.cppreference.com/w/cpp/utility/format/format_to
show `std::back_inserter(buffer)`.
There are multiple algorithms that work only with a single output iterator.

Question is should standard add a new adapter for input iterator for
filling bound ranges?
Something like `std::range_fill(std::ranges::range auto& x)` that
returns an output iterator that thrown when you try
write past the end.

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