malloc/malloc.h

   1 /* Prototypes and definition for malloc implementation.
   2    Copyright (C) 1996-2020 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
  61 /* Free a block allocated by `malloc', `realloc' or `calloc'.  */
  62 extern void free (void *__ptr) __THROW;
  63
  64 /* Allocate SIZE bytes allocated to ALIGNMENT bytes.  */
  65 extern void *memalign (size_t __alignment, size_t __size)
  66 __THROW __attribute_malloc__ __attribute_alloc_size__ ((2)) __wur;
  67
  68 /* Allocate SIZE bytes on a page boundary.  */
  69 extern void *valloc (size_t __size) __THROW __attribute_malloc__
  70      __attribute_alloc_size__ ((1)) __wur;
  71
  72 /* Equivalent to valloc(minimum-page-that-holds(n)), that is, round up
  73    __size to nearest pagesize. */
  74 extern void *pvalloc (size_t __size) __THROW __attribute_malloc__ __wur;
  75
  76 /* Underlying allocation function; successive calls should return
  77    contiguous pieces of memory.  */
  78 extern void *(*__morecore) (ptrdiff_t __size) __MALLOC_DEPRECATED;
  79
  80 /* Default value of `__morecore'.  */
  81 extern void *__default_morecore (ptrdiff_t __size)
  82 __THROW __attribute_malloc__  __MALLOC_DEPRECATED;
  83
  84 /* SVID2/XPG mallinfo structure */
  85
  86 struct mallinfo
  87 {
  88   int arena;    /* non-mmapped space allocated from system */
  89   int ordblks;  /* number of free chunks */
  90   int smblks;   /* number of fastbin blocks */
  91   int hblks;    /* number of mmapped regions */
  92   int hblkhd;   /* space in mmapped regions */
  93   int usmblks;  /* always 0, preserved for backwards compatibility */
  94   int fsmblks;  /* space available in freed fastbin blocks */
  95   int uordblks; /* total allocated space */
  96   int fordblks; /* total free space */
  97   int keepcost; /* top-most, releasable (via malloc_trim) space */
  98 };
  99
 100 /* SVID2/XPG mallinfo2 structure which can handle allocations
 101    bigger than 4GB.  */
 102
 103 struct mallinfo2
 104 {
 105   size_t arena;    /* non-mmapped space allocated from system */
 106   size_t ordblks;  /* number of free chunks */
 107   size_t smblks;   /* number of fastbin blocks */
 108   size_t hblks;    /* number of mmapped regions */
 109   size_t hblkhd;   /* space in mmapped regions */
 110   size_t usmblks;  /* always 0, preserved for backwards compatibility */
 111   size_t fsmblks;  /* space available in freed fastbin blocks */
 112   size_t uordblks; /* total allocated space */
 113   size_t fordblks; /* total free space */
 114   size_t keepcost; /* top-most, releasable (via malloc_trim) space */
 115 };
 116
 117 /* Returns a copy of the updated current mallinfo. */
 118 extern struct mallinfo mallinfo (void) __THROW __MALLOC_DEPRECATED;
 119
 120 /* Returns a copy of the updated current mallinfo. */
 121 extern struct mallinfo2 mallinfo2 (void) __THROW;
 122
 123 /* SVID2/XPG mallopt options */
 124 #ifndef M_MXFAST
 125 # define M_MXFAST  1    /* maximum request size for "fastbins" */
 126 #endif
 127 #ifndef M_NLBLKS
 128 # define M_NLBLKS  2    /* UNUSED in this malloc */
 129 #endif
 130 #ifndef M_GRAIN
 131 # define M_GRAIN   3    /* UNUSED in this malloc */
 132 #endif
 133 #ifndef M_KEEP
 134 # define M_KEEP    4    /* UNUSED in this malloc */
 135 #endif
 136
 137 /* mallopt options that actually do something */
 138 #define M_TRIM_THRESHOLD    -1
 139 #define M_TOP_PAD           -2
 140 #define M_MMAP_THRESHOLD    -3
 141 #define M_MMAP_MAX          -4
 142 #define M_CHECK_ACTION      -5
 143 #define M_PERTURB           -6
 144 #define M_ARENA_TEST        -7
 145 #define M_ARENA_MAX         -8
 146
 147 /* General SVID/XPG interface to tunable parameters. */
 148 extern int mallopt (int __param, int __val) __THROW;
 149
 150 /* Release all but __pad bytes of freed top-most memory back to the
 151    system. Return 1 if successful, else 0. */
 152 extern int malloc_trim (size_t __pad) __THROW;
 153
 154 /* Report the number of usable allocated bytes associated with allocated
 155    chunk __ptr. */
 156 extern size_t malloc_usable_size (void *__ptr) __THROW;
 157
 158 /* Prints brief summary statistics on stderr. */
 159 extern void malloc_stats (void) __THROW;
 160
 161 /* Output information about state of allocator to stream FP.  */
 162 extern int malloc_info (int __options, FILE *__fp) __THROW;
 163
 164 /* Hooks for debugging and user-defined versions. */
 165 extern void (*__MALLOC_HOOK_VOLATILE __free_hook) (void *__ptr,
 166                                                    const void *)
 167 __MALLOC_DEPRECATED;
 168 extern void *(*__MALLOC_HOOK_VOLATILE __malloc_hook)(size_t __size,
 169                                                      const void *)
 170 __MALLOC_DEPRECATED;
 171 extern void *(*__MALLOC_HOOK_VOLATILE __realloc_hook)(void *__ptr,
 172                                                       size_t __size,
 173                                                       const void *)
 174 __MALLOC_DEPRECATED;
 175 extern void *(*__MALLOC_HOOK_VOLATILE __memalign_hook)(size_t __alignment,
 176                                                        size_t __size,
 177                                                        const void *)
 178 __MALLOC_DEPRECATED;
 179 extern void (*__MALLOC_HOOK_VOLATILE __after_morecore_hook) (void)
 180   __MALLOC_DEPRECATED;
 181
 182
 183 __END_DECLS
 184 #endif /* malloc.h */