You (or your copilot) seem to have missed the point behind object lifetimes. The vector values' lifetimes are being ended. They no longer exist.

There exists a residual bit pattern in that space that you're mistaking for the values that used to be there.

Your "radical fix" is to force it to do extra work, paging in memory and invalidating cache lines, for memory that does not contain any live objects. I do not think there is any value in that, especially not given that C++26 has added hardened preconditions that actively stop you from even looking at those values inside your software without first creating a new object in their space invalidating the data currently there.

Even the "soft fix" is adding documentation to a function that has been used for over a quarter century. If people haven't been able to understand what it does by now... I don't think adding that to documentation - or the c++ standard, which seems to be what you're suggesting? - is of any meaning.

Not to mention that this function has 25+ years of deployment and experience. Have you tried searching for how often this is used in any code anywhere?

PS: I do not care whether you use any AI tools. I will assume you are taking full responsibility for what your email contains regardless if you used autocorrect, autocomplete or auto-write-my-whole-proposal. And your remaining goodwill will reduce if it's terrible.

On Tue, Oct 7, 2025 at 10:12 PM Jerome Saint-Martin via Std-Proposals <std-proposals@lists.isocpp.org> wrote:

Motivation

In the Standard Template Library (STL), the clear() function is defined for containers like std::vector, std::deque, and others. Its behavior is functionally equivalent to:

container.erase(container.begin(), container.end());

It removes all elements from the container, reducing its size() to zero, but does not release memory (capacity remains unchanged), nor does it reset values. This leads to a subtle redundancy in the API: clear() is essentially a shorthand for a full-range erase().

Observation

While clear() is widely used and syntactically convenient, it introduces a semantic ambiguity. Many developers — especially those new to C++ — assume clear() “resets” the container’s values. In reality, it destroys the elements, not reinitializes them.

This confusion is compounded by the fact that clear() does not offer anything beyond what erase(begin(), end()) already provides.

Too Much Progress Kills the Progress

In the early days of programming, we used erase(begin(), end()) like our ancestors used silex to make fire. It was precise, intentional, and part of the craft. Then came clear() — a smoother, more modern tool. But in simplifying, we may have blurred its purpose. Today, we have expressive tools like resize(n, val), ranges, and lambdas.

Proposal

Option A (radical):

Deprecate or remove clear() from STL containers where it is strictly equivalent to erase(begin(), end())

reclaim clear() for a more meaningful role — resetting vector values to a default value, like resize(n, val) does — and let erase(begin(), end()) remain the sharp silex in our toolbox.

Option B (soft): Clarify in the standard documentation that clear() is a semantic alias for erase(begin(), end()), and does not reset values or release memory.

std::co_proposers :: Jérôme Saint-Martin and friend Beg Copilot

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