malloc/malloc.h

   1 /* Prototypes and definition for malloc implementation.
   2    Copyright (C) 1996-2024 Free Software Foundation, Inc.
   3    Copyright The GNU Toolchain Authors.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #ifndef _MALLOC_H
  21 #define _MALLOC_H 1
  22
  23 #include <features.h>
  24 #include <stddef.h>
  25 #include <stdio.h>
  26
  27 #ifdef _LIBC
  28 # define __MALLOC_HOOK_VOLATILE
  29 # define __MALLOC_DEPRECATED
  30 #else
  31 # define __MALLOC_HOOK_VOLATILE volatile
  32 # define __MALLOC_DEPRECATED __attribute_deprecated__
  33 #endif
  34
  35
  36 __BEGIN_DECLS
  37
  38 /* Allocate SIZE bytes of memory.  */
  39 extern void *malloc (size_t __size) __THROW __attribute_malloc__
  40      __attribute_alloc_size__ ((1)) __wur;
  41
  42 /* Allocate NMEMB elements of SIZE bytes each, all initialized to 0.  */
  43 extern void *calloc (size_t __nmemb, size_t __size)
  44 __THROW __attribute_malloc__ __attribute_alloc_size__ ((1, 2)) __wur;
  45
  46 /* Re-allocate the previously allocated block in __ptr, making the new
  47    block SIZE bytes long.  */
  48 /* __attribute_malloc__ is not used, because if realloc returns
  49    the same pointer that was passed to it, aliasing needs to be allowed
  50    between objects pointed by the old and new pointers.  */
  51 extern void *realloc (void *__ptr, size_t __size)
  52 __THROW __attribute_warn_unused_result__ __attribute_alloc_size__ ((2));
  53
  54 /* Re-allocate the previously allocated block in PTR, making the new
  55    block large enough for NMEMB elements of SIZE bytes each.  */
  56 /* __attribute_malloc__ is not used, because if reallocarray returns
  57    the same pointer that was passed to it, aliasing needs to be allowed
  58    between objects pointed by the old and new pointers.  */
  59 extern void *reallocarray (void *__ptr, size_t __nmemb, size_t __size)
  60   __THROW __attribute_warn_unused_result__ __attribute_alloc_size__ ((2, 3))
  61   __attr_dealloc_free;
  62
  63 /* Free a block allocated by `malloc', `realloc' or `calloc'.  */
  64 extern void free (void *__ptr) __THROW;
  65
  66 /* Allocate SIZE bytes allocated to ALIGNMENT bytes.  */
  67 extern void *memalign (size_t __alignment, size_t __size)
  68   __THROW __attribute_malloc__ __attribute_alloc_align__ ((1))
  69   __attribute_alloc_size__ ((2)) __wur __attr_dealloc_free;
  70
  71 /* Allocate SIZE bytes on a page boundary.  */
  72 extern void *valloc (size_t __size) __THROW __attribute_malloc__
  73      __attribute_alloc_size__ ((1)) __wur __attr_dealloc_free;
  74
  75 /* Equivalent to valloc(minimum-page-that-holds(n)), that is, round up
  76    __size to nearest pagesize. */
  77 extern void *pvalloc (size_t __size) __THROW __attribute_malloc__
  78   __wur __attr_dealloc_free;
  79
  80 /* SVID2/XPG mallinfo structure */
  81
  82 struct mallinfo
  83 {
  84   int arena;    /* non-mmapped space allocated from system */
  85   int ordblks;  /* number of free chunks */
  86   int smblks;   /* number of fastbin blocks */
  87   int hblks;    /* number of mmapped regions */
  88   int hblkhd;   /* space in mmapped regions */
  89   int usmblks;  /* always 0, preserved for backwards compatibility */
  90   int fsmblks;  /* space available in freed fastbin blocks */
  91   int uordblks; /* total allocated space */
  92   int fordblks; /* total free space */
  93   int keepcost; /* top-most, releasable (via malloc_trim) space */
  94 };
  95
  96 /* SVID2/XPG mallinfo2 structure which can handle allocations
  97    bigger than 4GB.  */
  98
  99 struct mallinfo2
 100 {
 101   size_t arena;    /* non-mmapped space allocated from system */
 102   size_t ordblks;  /* number of free chunks */
 103   size_t smblks;   /* number of fastbin blocks */
 104   size_t hblks;    /* number of mmapped regions */
 105   size_t hblkhd;   /* space in mmapped regions */
 106   size_t usmblks;  /* always 0, preserved for backwards compatibility */
 107   size_t fsmblks;  /* space available in freed fastbin blocks */
 108   size_t uordblks; /* total allocated space */
 109   size_t fordblks; /* total free space */
 110   size_t keepcost; /* top-most, releasable (via malloc_trim) space */
 111 };
 112
 113 /* Returns a copy of the updated current mallinfo. */
 114 extern struct mallinfo mallinfo (void) __THROW __MALLOC_DEPRECATED;
 115
 116 /* Returns a copy of the updated current mallinfo. */
 117 extern struct mallinfo2 mallinfo2 (void) __THROW;
 118
 119 /* SVID2/XPG mallopt options */
 120 #ifndef M_MXFAST
 121 # define M_MXFAST  1    /* maximum request size for "fastbins" */
 122 #endif
 123 #ifndef M_NLBLKS
 124 # define M_NLBLKS  2    /* UNUSED in this malloc */
 125 #endif
 126 #ifndef M_GRAIN
 127 # define M_GRAIN   3    /* UNUSED in this malloc */
 128 #endif
 129 #ifndef M_KEEP
 130 # define M_KEEP    4    /* UNUSED in this malloc */
 131 #endif
 132
 133 /* mallopt options that actually do something */
 134 #define M_TRIM_THRESHOLD    -1
 135 #define M_TOP_PAD           -2
 136 #define M_MMAP_THRESHOLD    -3
 137 #define M_MMAP_MAX          -4
 138 #define M_CHECK_ACTION      -5
 139 #define M_PERTURB           -6
 140 #define M_ARENA_TEST        -7
 141 #define M_ARENA_MAX         -8
 142
 143 /* General SVID/XPG interface to tunable parameters. */
 144 extern int mallopt (int __param, int __val) __THROW;
 145
 146 /* Release all but __pad bytes of freed top-most memory back to the
 147    system. Return 1 if successful, else 0. */
 148 extern int malloc_trim (size_t __pad) __THROW;
 149
 150 /* Report the number of usable allocated bytes associated with allocated
 151    chunk __ptr. */
 152 extern size_t malloc_usable_size (void *__ptr) __THROW;
 153
 154 /* Prints brief summary statistics on stderr. */
 155 extern void malloc_stats (void) __THROW;
 156
 157 /* Output information about state of allocator to stream FP.  */
 158 extern int malloc_info (int __options, FILE *__fp) __THROW;
 159
 160 __END_DECLS
 161 #endif /* malloc.h */