Crate memapi2 

A small, no_std/no_alloc-friendly memory allocation interface for managing raw buffers.

This crate provides explicit layouts, a split allocator trait stack, and structured errors. It is no_std by default but relies on the alloc crate unless no_alloc is enabled. Enable std for system allocator integrations and os_err_reporting for richer diagnostics.

Core traits

• Alloc, Dealloc, Grow, Shrink, Realloc
• Convenience aliases: BasicAlloc and FullAlloc
• Mutable variants in alloc_mut: AllocMut, DeallocMut, GrowMut, ShrinkMut, ReallocMut, BasicAllocMut, FullAllocMut
• Optional scoped allocations (alloc_temp_trait feature): AllocTemp

Types and errors

• Layout: crate layout type (with conversion to/from StdLayout unless no_alloc is enabled and std isn’t)
• DefaultAlloc: default allocator wrapper that delegates to the global allocator
• Errors: Error, Cause, LayoutErr, ArithErr, ArithOp

Data and type utilities

• traits::data::type_props: SizedProps, PtrProps, VarSized, VarSizedStruct
• traits::data::marker: UnsizedCopy, Thin, SizeMeta
• helpers: alignment, checked arithmetic, and pointer helpers

Allocator implementations

• DefaultAlloc (available unless no_alloc is enabled and std isn’t)
• System when the std feature is enabled
• CAlloc behind the c_alloc feature
• StackAlloc behind the stack_alloc feature

Feature flags

• no_alloc disables usage of the rust alloc crate; std crate is used instead if the std feature is enabled.
• std: enables std integration (including System)
• os_err_reporting: best-effort OS error reporting via errno (requires std)
• alloc_temp_trait: scoped/temporary allocation trait
• c_alloc: C posix_memalign-style allocator (allocs::c_alloc)
• stack_alloc: alloca-based allocator (allocs::stack_alloc)
• c_str: enables CStr-specific data traits in no_std (MSRV: 1.64)
• metadata: enables core::ptr::Pointee metadata support on nightly
• sized_hierarchy: enables core::marker::MetaSized support on nightly
• full, full_nightly: convenience bundles

Modules

allocs

Additional allocators which this crate supports.

error

Errors that can occur during allocation.

ffi

FFI backing any extra enabled allocators.

helpers

Helpers that tend to be useful in other libraries as well.

layout

A custom layout type to get around some strange Rust stdlib limitations.

prelude

A relatively minimal prelude containing the most common, important things from this crate.

traits

All traits provided by this crate.

Structs

DefaultAlloc

Default allocator, delegating to the global allocator.