Why is my first C++ (m)allocation always 72 KB?

Buobe IA context · why it matters

The C++ standard library allocates an emergency pool for exception handling — This ensures robust error management but can lead to initial allocations larger than expected.
Overriding default malloc with custom implementations requires understanding these underlying mechanisms — Developers must account for such memory setups when testing and optimizing their own allocators.

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EDIT (March 1, 2026): I updated the title to to clarify that this observation is specific to my environment. The original title may have implied a universal behavior, which isn’t the case.

First Allocation Always

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