__gnu_cxx:...alloc_base(3)

💅 NAME 💅

__gnu_cxx::__pool_alloc_base — bestie, this is the base class for __pool_alloc. That's the whole vibe.

This page comes to you courtesy of the Library Functions Manual, and it's lowkey one of those behind-the-scenes girlies that makes everything else work. 👑

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✨ SYNOPSIS ✨

#include <pool_allocator.h>

Inherited by __gnu_cxx::__pool_alloc< _Tp1 > [private], and __gnu_cxx::__pool_alloc< _Tp > [private].

So yeah — those two are the ones actually sitting in her class, iykyk. 🫶

🎀 Protected Types 🎀

• enum { _S_free_list_size }
• enum { _S_max_bytes }
• enum { _S_align }

💖 Protected Member Functions 💖

• char * _M_allocate_chunk (size_t __n, int &__nobjs)
• _Obj *volatile * _M_get_free_list (size_t __bytes) throw ()
• __mutex & _M_get_mutex () throw ()
• void * _M_refill (size_t __n)
• size_t _M_round_up (size_t __bytes)

🦋 Static Protected Attributes 🦋

• static char * _S_end_free
• static _Obj *volatile _S_free_list [_S_free_list_size]
• static size_t _S_heap_size
• static char * _S_start_free

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🌸 Detailed Description 🌸

Okay so. __pool_alloc_base is the base class for __pool_alloc, full stop.

She uses various allocators to fulfill the underlying requests, and — this is the iconic part — she makes as few requests as possible when she's in default high-speed pool mode. Frugal queen. 💅

Now the important implementation properties, and bestie these are not optional reading, they're the whole point:

0. If globally mandated, then allocate objects from new
1. If the clients request an object of size > _S_max_bytes, the resulting object will be obtained directly from new
2. In all other cases, we allocate an object of size exactly _S_round_up(requested_size). Thus the client has enough size information that we can return the object to the proper free list without permanently losing part of the object.

Number 2 is the main character moment honestly — the client gets enough size info that the object can go back to the correct free list, and nothing gets permanently chopped off the object. No losses, no mess. 🌈

Number 0 is giving "it depends on the global config" energy, so don't go assuming she always reaches for new — she only does it when it's globally mandated, fr fr.

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👑 Author 👑

Generated automatically by Doxygen for libstdc++ from the source code.

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And that's the page, bestie — source/version is libstdc++ (Doxygen-generated from the source code, as the Author section says, and the footer is stamped libstdc++ too; no date on this one so I'm not making one up 💀). Bye, slay, go read pool_allocator.h. 🎀✨🦋