include/qemu/memalign.h

   1 /*
   2  * Allocation and free functions for aligned memory
   3  *
   4  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   5  * See the COPYING file in the top-level directory.
   6  */
   7
   8 #ifndef QEMU_MEMALIGN_H
   9 #define QEMU_MEMALIGN_H
  10
  11 /**
  12  * qemu_try_memalign: Allocate aligned memory
  13  * @alignment: required alignment, in bytes
  14  * @size: size of allocation, in bytes
  15  *
  16  * Allocate memory on an aligned boundary (i.e. the returned
  17  * address will be an exact multiple of @alignment).
  18  * @alignment must be a power of 2, or the function will assert().
  19  * On success, returns allocated memory; on failure, returns NULL.
  20  *
  21  * The memory allocated through this function must be freed via
  22  * qemu_vfree() (and not via free()).
  23  */
  24 void *qemu_try_memalign(size_t alignment, size_t size);
  25 /**
  26  * qemu_memalign: Allocate aligned memory, without failing
  27  * @alignment: required alignment, in bytes
  28  * @size: size of allocation, in bytes
  29  *
  30  * Allocate memory in the same way as qemu_try_memalign(), but
  31  * abort() with an error message if the memory allocation fails.
  32  *
  33  * The memory allocated through this function must be freed via
  34  * qemu_vfree() (and not via free()).
  35  */
  36 void *qemu_memalign(size_t alignment, size_t size);
  37 /**
  38  * qemu_vfree: Free memory allocated through qemu_memalign
  39  * @ptr: memory to free
  40  *
  41  * This function must be used to free memory allocated via qemu_memalign()
  42  * or qemu_try_memalign(). (Using the wrong free function will cause
  43  * subtle bugs on Windows hosts.)
  44  */
  45 void qemu_vfree(void *ptr);
  46 /*
  47  * It's an analog of GLIB's g_autoptr_cleanup_generic_gfree(), used to define
  48  * g_autofree macro.
  49  */
  50 static inline void qemu_cleanup_generic_vfree(void *p)
  51 {
  52   void **pp = (void **)p;
  53   qemu_vfree(*pp);
  54 }
  55
  56 /*
  57  * Analog of g_autofree, but qemu_vfree is called on cleanup instead of g_free.
  58  */
  59 #define QEMU_AUTO_VFREE __attribute__((cleanup(qemu_cleanup_generic_vfree)))
  60
  61 #endif