microlisp_allocator Struct Reference

Caller-supplied allocator. More...

#include <microlisp.h>

Data Fields
void *(*	alloc )(size_t size, void *user)
	Allocate size bytes.
void(*	free )(void *ptr, void *user)
	Free a pointer previously returned by alloc.
void *	user
	Opaque user data passed verbatim to alloc and free.

Detailed Description

Caller-supplied allocator.

Pass NULL to microlisp_state_create to use the platform malloc / free.

The implementation only calls alloc and free; it does not call realloc, calloc, or memalign.

Thread safety: the caller's alloc / free functions must

themselves be MT-Safe if the microlisp_allocator is shared across threads (i.e. used to construct multiple states that run concurrently).

Field Documentation

alloc

void *(* microlisp_allocator::alloc) (size_t size, void *user)

Allocate size bytes.

Returns NULL on failure. Must be non-NULL whenever the surrounding microlisp_allocator struct is non-NULL.

Alignment contract: every returned non-NULL pointer must be aligned to at least 8 bytes (alignof(uint64_t)). The interpreter's value representation reserves the low 3 bits of heap-object pointers for a type tag; allocators that return weaker alignment (1- or 4-byte) will silently corrupt values on the first GC cycle. Platform malloc always meets this on any supported target; custom arenas must round up explicitly.

free

void(* microlisp_allocator::free) (void *ptr, void *user)

Free a pointer previously returned by alloc.

Must be non-NULL whenever the surrounding microlisp_allocator struct is non-NULL. free(NULL) is a no-op.

user

void* microlisp_allocator::user

Opaque user data passed verbatim to alloc and free.

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The documentation for this struct was generated from the following file:

• include/microlisp/microlisp.h