malloc/malloc.h

   1 /* Prototypes and definition for malloc implementation.
   2    Copyright (C) 1996-2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _MALLOC_H
  20 #define _MALLOC_H 1
  21
  22 #include <features.h>
  23 #include <stddef.h>
  24 #include <stdio.h>
  25
  26 #ifdef _LIBC
  27 # define __MALLOC_HOOK_VOLATILE
  28 # define __MALLOC_DEPRECATED
  29 #else
  30 # define __MALLOC_HOOK_VOLATILE volatile
  31 # define __MALLOC_DEPRECATED __attribute_deprecated__
  32 #endif
  33
  34
  35 __BEGIN_DECLS
  36
  37 /* Allocate SIZE bytes of memory.  */
  38 extern void *malloc (size_t __size) __THROW __attribute_malloc__
  39      __attribute_alloc_size__ ((1)) __wur;
  40
  41 /* Allocate NMEMB elements of SIZE bytes each, all initialized to 0.  */
  42 extern void *calloc (size_t __nmemb, size_t __size)
  43 __THROW __attribute_malloc__ __attribute_alloc_size__ ((1, 2)) __wur;
  44
  45 /* Re-allocate the previously allocated block in __ptr, making the new
  46    block SIZE bytes long.  */
  47 /* __attribute_malloc__ is not used, because if realloc returns
  48    the same pointer that was passed to it, aliasing needs to be allowed
  49    between objects pointed by the old and new pointers.  */
  50 extern void *realloc (void *__ptr, size_t __size)
  51 __THROW __attribute_warn_unused_result__ __attribute_alloc_size__ ((2));
  52
  53 /* Re-allocate the previously allocated block in PTR, making the new
  54    block large enough for NMEMB elements of SIZE bytes each.  */
  55 /* __attribute_malloc__ is not used, because if reallocarray returns
  56    the same pointer that was passed to it, aliasing needs to be allowed
  57    between objects pointed by the old and new pointers.  */
  58 extern void *reallocarray (void *__ptr, size_t __nmemb, size_t __size)
  59   __THROW __attribute_warn_unused_result__ __attribute_alloc_size__ ((2, 3))
  60   __attr_dealloc_free;
  61
  62 /* Free a block allocated by `malloc', `realloc' or `calloc'.  */
  63 extern void free (void *__ptr) __THROW;
  64
  65 /* Allocate SIZE bytes allocated to ALIGNMENT bytes.  */
  66 extern void *memalign (size_t __alignment, size_t __size)
  67   __THROW __attribute_malloc__ __attribute_alloc_size__ ((2)) __wur
  68   __attr_dealloc_free;
  69
  70 /* Allocate SIZE bytes on a page boundary.  */
  71 extern void *valloc (size_t __size) __THROW __attribute_malloc__
  72      __attribute_alloc_size__ ((1)) __wur __attr_dealloc_free;
  73
  74 /* Equivalent to valloc(minimum-page-that-holds(n)), that is, round up
  75    __size to nearest pagesize. */
  76 extern void *pvalloc (size_t __size) __THROW __attribute_malloc__
  77   __wur __attr_dealloc_free;
  78
  79 /* SVID2/XPG mallinfo structure */
  80
  81 struct mallinfo
  82 {
  83   int arena;    /* non-mmapped space allocated from system */
  84   int ordblks;  /* number of free chunks */
  85   int smblks;   /* number of fastbin blocks */
  86   int hblks;    /* number of mmapped regions */
  87   int hblkhd;   /* space in mmapped regions */
  88   int usmblks;  /* always 0, preserved for backwards compatibility */
  89   int fsmblks;  /* space available in freed fastbin blocks */
  90   int uordblks; /* total allocated space */
  91   int fordblks; /* total free space */
  92   int keepcost; /* top-most, releasable (via malloc_trim) space */
  93 };
  94
  95 /* SVID2/XPG mallinfo2 structure which can handle allocations
  96    bigger than 4GB.  */
  97
  98 struct mallinfo2
  99 {
 100   size_t arena;    /* non-mmapped space allocated from system */
 101   size_t ordblks;  /* number of free chunks */
 102   size_t smblks;   /* number of fastbin blocks */
 103   size_t hblks;    /* number of mmapped regions */
 104   size_t hblkhd;   /* space in mmapped regions */
 105   size_t usmblks;  /* always 0, preserved for backwards compatibility */
 106   size_t fsmblks;  /* space available in freed fastbin blocks */
 107   size_t uordblks; /* total allocated space */
 108   size_t fordblks; /* total free space */
 109   size_t keepcost; /* top-most, releasable (via malloc_trim) space */
 110 };
 111
 112 /* Returns a copy of the updated current mallinfo. */
 113 extern struct mallinfo mallinfo (void) __THROW __MALLOC_DEPRECATED;
 114
 115 /* Returns a copy of the updated current mallinfo. */
 116 extern struct mallinfo2 mallinfo2 (void) __THROW;
 117
 118 /* SVID2/XPG mallopt options */
 119 #ifndef M_MXFAST
 120 # define M_MXFAST  1    /* maximum request size for "fastbins" */
 121 #endif
 122 #ifndef M_NLBLKS
 123 # define M_NLBLKS  2    /* UNUSED in this malloc */
 124 #endif
 125 #ifndef M_GRAIN
 126 # define M_GRAIN   3    /* UNUSED in this malloc */
 127 #endif
 128 #ifndef M_KEEP
 129 # define M_KEEP    4    /* UNUSED in this malloc */
 130 #endif
 131
 132 /* mallopt options that actually do something */
 133 #define M_TRIM_THRESHOLD    -1
 134 #define M_TOP_PAD           -2
 135 #define M_MMAP_THRESHOLD    -3
 136 #define M_MMAP_MAX          -4
 137 #define M_CHECK_ACTION      -5
 138 #define M_PERTURB           -6
 139 #define M_ARENA_TEST        -7
 140 #define M_ARENA_MAX         -8
 141
 142 /* General SVID/XPG interface to tunable parameters. */
 143 extern int mallopt (int __param, int __val) __THROW;
 144
 145 /* Release all but __pad bytes of freed top-most memory back to the
 146    system. Return 1 if successful, else 0. */
 147 extern int malloc_trim (size_t __pad) __THROW;
 148
 149 /* Report the number of usable allocated bytes associated with allocated
 150    chunk __ptr. */
 151 extern size_t malloc_usable_size (void *__ptr) __THROW;
 152
 153 /* Prints brief summary statistics on stderr. */
 154 extern void malloc_stats (void) __THROW;
 155
 156 /* Output information about state of allocator to stream FP.  */
 157 extern int malloc_info (int __options, FILE *__fp) __THROW;
 158
 159 __END_DECLS
 160 #endif /* malloc.h */