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.\"
.\" Copyright (c) 2026 Faraz Vahedi <kfv@kfv.io>
.\"
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
.Dd May 17, 2026
.Dt FREE_SIZED 3
.Os
.Sh NAME
.Nm free_sized ,
.Nm free_aligned_sized
.Nd C23 sized deallocation functions
.Sh SYNOPSIS
.Lb libc
.In stdlib.h
.Ft void
.Fn free_sized "void *ptr" "size_t size"
.Ft void
.Fn free_aligned_sized "void *ptr" "size_t alignment" "size_t size"
.Sh DESCRIPTION
The
.Fn free_sized
function deallocates the memory referenced by
.Fa ptr
that was previously allocated by
.Xr malloc 3 ,
.Xr realloc 3 ,
or
.Xr calloc 3 .
The
.Fa size
argument shall equal the size passed to the allocation function.
The result of an
.Xr aligned_alloc 3
may not be passed to
.Fn free_sized .
.Pp
The
.Fn free_aligned_sized
function deallocates memory referenced by
.Fa ptr
that was previously allocated by
.Xr aligned_alloc 3 .
The
.Fa alignment
and
.Fa size
arguments shall equal the values supplied to the allocation function.
The result of an
.Xr malloc 3 ,
.Xr calloc 3 ,
or
.Xr realloc 3
may not be passed to
.Fn free_aligned_sized .
.Pp
If
.Fa ptr
is neither a null pointer nor a pointer returned by the allocation functions
described above for the corresponding deallocation function, the behaviour is
undefined, and so is supplying a
.Fa size
or
.Fa alignment
that does not match the original allocation.
.Sh IMPLEMENTATION NOTES
The C standard permits an implementation to ignore the
.Fa size
and
.Fa alignment
hints.
The current implementation forwards to
.Xr free 3
without validating these arguments, so behaviour remains correct for
well-formed use.
.Pp
These functions will be wired to the system allocator's sized deallocation,
once supported, as with the rest of the memory allocation API, so that
.Fa size
and
.Fa alignment
hints are used for performance and security benefits.
That behaviour conforms to the practice recommended for each function in the
C standard.
.Sh SEE ALSO
.Xr aligned_alloc 3 ,
.Xr calloc 3 ,
.Xr free 3 ,
.Xr jemalloc 3 ,
.Xr malloc 3 ,
.Xr realloc 3
.Sh STANDARDS
The
.Fn free_sized
and
.Fn free_aligned_sized
functions conform to
.St -isoC-2023 .
.Sh AUTHOR
.An Faraz Vahedi Aq Mt kfv@kfv.io
|
