emacs/lib/allocator.h

/* Memory allocators such as malloc+free.

   Copyright (C) 2011 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* Written by Paul Eggert.  */

#ifndef _GL_ALLOCATOR_H
#define _GL_ALLOCATOR_H

#include <stddef.h>

/* An object describing a memory allocator family.  */

struct allocator
{
  /* Do not use GCC attributes such as __attribute__ ((malloc)) with
     the function types pointed at by these members, because these
     attributes do not work with pointers to functions.  See
     <http://lists.gnu.org/archive/html/bug-gnulib/2011-04/msg00007.html>.  */

  /* Call ALLOCATE to allocate memory, like 'malloc'.  On failure ALLOCATE
     should return NULL, though not necessarily set errno.  When given
     a zero size it may return NULL even if successful.  */
  void *(*allocate) (size_t);

  /* If nonnull, call REALLOCATE to reallocate memory, like 'realloc'.
     On failure REALLOCATE should return NULL, though not necessarily set
     errno.  When given a zero size it may return NULL even if
     successful.  */
  void *(*reallocate) (void *, size_t);

  /* Call FREE to free memory, like 'free'.  */
  void (*free) (void *);

  /* If nonnull, call DIE if MALLOC or REALLOC fails.  DIE should not
     return.  DIE can be used by code that detects memory overflow
     while calculating sizes to be passed to MALLOC or REALLOC.  */
  void (*die) (void);
};

/* An allocator using the stdlib functions and a null DIE function.  */
extern struct allocator const stdlib_allocator;

#endif /* _GL_ALLOCATOR_H */