Simplify malloc code

Remove all kinds of unused configuration options and dead code.

1 files changed, 203 insertions, 1447 deletions

diff --git a/malloc/malloc.c b/malloc/malloc.c
index d7af63dae5..0683eee2a1 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -74,20 +74,20 @@
   Standard (ANSI/SVID/...)  functions:
     malloc(size_t n);
     calloc(size_t n_elements, size_t element_size);
-    free(Void_t* p);
-    realloc(Void_t* p, size_t n);
+    free(void* p);
+    realloc(void* p, size_t n);
     memalign(size_t alignment, size_t n);
     valloc(size_t n);
     mallinfo()
     mallopt(int parameter_number, int parameter_value)
 
   Additional functions:
-    independent_calloc(size_t n_elements, size_t size, Void_t* chunks[]);
-    independent_comalloc(size_t n_elements, size_t sizes[], Void_t* chunks[]);
+    independent_calloc(size_t n_elements, size_t size, void* chunks[]);
+    independent_comalloc(size_t n_elements, size_t sizes[], void* chunks[]);
     pvalloc(size_t n);
-    cfree(Void_t* p);
+    cfree(void* p);
     malloc_trim(size_t pad);
-    malloc_usable_size(Void_t* p);
+    malloc_usable_size(void* p);
     malloc_stats();
 
 * Vital statistics:
@@ -145,7 +145,7 @@
        failure action and then return null. (Requests may also
        also fail because a system is out of memory.)
 
-  Thread-safety: thread-safe unless NO_THREADS is defined
+  Thread-safety: thread-safe
 
   Compliance: I believe it is compliant with the 1997 Single Unix Specification
        Also SVID/XPG, ANSI C, and probably others as well.
@@ -154,8 +154,7 @@
 
     People have reported using previous versions of this malloc on all
     versions of Unix, sometimes by tweaking some of the defines
-    below. It has been tested most extensively on Solaris and
-    Linux. It is also reported to work on WIN32 platforms.
+    below. It has been tested most extensively on Solaris and Linux.
     People also report using it in stand-alone embedded systems.
 
     The implementation is in straight, hand-tuned ANSI C.  It is not
@@ -170,19 +169,8 @@
 
     Compilation Environment options:
 
-    __STD_C                    derived from C compiler defines
-    WIN32                      NOT defined
-    HAVE_MEMCPY                defined
-    USE_MEMCPY                 1 if HAVE_MEMCPY is defined
-    HAVE_MMAP                  defined as 1
-    MMAP_CLEARS                1
     HAVE_MREMAP                0 unless linux defined
-    USE_ARENAS                 the same as HAVE_MMAP
     malloc_getpagesize         derived from system #includes, or 4096 if not
-    HAVE_USR_INCLUDE_MALLOC_H  NOT defined
-    LACKS_UNISTD_H             NOT defined unless WIN32
-    LACKS_SYS_PARAM_H          NOT defined unless WIN32
-    LACKS_SYS_MMAN_H           NOT defined unless WIN32
 
     Changing default word sizes:
 
@@ -197,7 +185,7 @@
     USE_MALLOC_LOCK            NOT defined
     MALLOC_DEBUG               NOT defined
     REALLOC_ZERO_BYTES_FREES   1
-    MALLOC_FAILURE_ACTION      errno = ENOMEM, if __STD_C defined, else no-op
+    MALLOC_FAILURE_ACTION      errno = ENOMEM
     TRIM_FASTBINS              0
 
     Options for customizing MORECORE:
@@ -221,67 +209,28 @@
     probably don't want to touch unless you are extending or adapting malloc.  */
 
 /*
-  __STD_C should be nonzero if using ANSI-standard C compiler, a C++
-  compiler, or a C compiler sufficiently close to ANSI to get away
-  with it.
+  void* is the pointer type that malloc should say it returns
 */
 
-#ifndef __STD_C
-#if defined(__STDC__) || defined(__cplusplus)
-#define __STD_C     1
-#else
-#define __STD_C     0
-#endif
-#endif /*__STD_C*/
-
-
-/*
-  Void_t* is the pointer type that malloc should say it returns
-*/
-
-#ifndef Void_t
-#if (__STD_C || defined(WIN32))
-#define Void_t      void
-#else
-#define Void_t      char
-#endif
-#endif /*Void_t*/
+#ifndef void
+#define void      void
+#endif /*void*/
 
-#if __STD_C
 #include <stddef.h>   /* for size_t */
 #include <stdlib.h>   /* for getenv(), abort() */
-#else
-#include <sys/types.h>
-#endif
 
 #include <malloc-machine.h>
 
-#ifdef _LIBC
-#ifdef ATOMIC_FASTBINS
 #include <atomic.h>
-#endif
 #include <stdio-common/_itoa.h>
 #include <bits/wordsize.h>
 #include <sys/sysinfo.h>
-#endif
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-/* define LACKS_UNISTD_H if your system does not have a <unistd.h>. */
-
-/* #define  LACKS_UNISTD_H */
-
-#ifndef LACKS_UNISTD_H
 #include <unistd.h>
-#endif
-
-/* define LACKS_SYS_PARAM_H if your system does not have a <sys/param.h>. */
-
-/* #define  LACKS_SYS_PARAM_H */
-
-
 #include <stdio.h>    /* needed for malloc_stats */
 #include <errno.h>    /* needed for optional MALLOC_FAILURE_ACTION */
 
@@ -486,7 +435,6 @@ __malloc_assert (const char *assertion, const char *file, unsigned int line,
 #define public_gET_STATe dlget_state
 #define public_sET_STATe dlset_state
 #else /* USE_DL_PREFIX */
-#ifdef _LIBC
 
 /* Special defines for the GNU C library.  */
 #define public_cALLOc    __libc_calloc
@@ -515,79 +463,13 @@ __malloc_assert (const char *assertion, const char *file, unsigned int line,
 #define MORECORE         (*__morecore)
 #define MORECORE_FAILURE 0
 
-Void_t * __default_morecore (ptrdiff_t);
-Void_t *(*__morecore)(ptrdiff_t) = __default_morecore;
-
-#else /* !_LIBC */
-#define public_cALLOc    calloc
-#define public_fREe      free
-#define public_cFREe     cfree
-#define public_mALLOc    malloc
-#define public_mEMALIGn  memalign
-#define public_rEALLOc   realloc
-#define public_vALLOc    valloc
-#define public_pVALLOc   pvalloc
-#define public_mALLINFo  mallinfo
-#define public_mALLOPt   mallopt
-#define public_mTRIm     malloc_trim
-#define public_mSTATs    malloc_stats
-#define public_mUSABLe   malloc_usable_size
-#define public_iCALLOc   independent_calloc
-#define public_iCOMALLOc independent_comalloc
-#define public_gET_STATe malloc_get_state
-#define public_sET_STATe malloc_set_state
-#endif /* _LIBC */
-#endif /* USE_DL_PREFIX */
-
-#ifndef _LIBC
-#define __builtin_expect(expr, val)	(expr)
-
-#define fwrite(buf, size, count, fp) _IO_fwrite (buf, size, count, fp)
-#endif
-
-/*
-  HAVE_MEMCPY should be defined if you are not otherwise using
-  ANSI STD C, but still have memcpy and memset in your C library
-  and want to use them in calloc and realloc. Otherwise simple
-  macro versions are defined below.
-
-  USE_MEMCPY should be defined as 1 if you actually want to
-  have memset and memcpy called. People report that the macro
-  versions are faster than libc versions on some systems.
-
-  Even if USE_MEMCPY is set to 1, loops to copy/clear small chunks
-  (of <= 36 bytes) are manually unrolled in realloc and calloc.
-*/
-
-#define HAVE_MEMCPY
-
-#ifndef USE_MEMCPY
-#ifdef HAVE_MEMCPY
-#define USE_MEMCPY 1
-#else
-#define USE_MEMCPY 0
-#endif
-#endif
+void * __default_morecore (ptrdiff_t);
+void *(*__morecore)(ptrdiff_t) = __default_morecore;
 
+#endif /* USE_DL_PREFIX */
 
-#if (__STD_C || defined(HAVE_MEMCPY))
 
-#ifdef _LIBC
-# include <string.h>
-#else
-#ifdef WIN32
-/* On Win32 memset and memcpy are already declared in windows.h */
-#else
-#if __STD_C
-void* memset(void*, int, size_t);
-void* memcpy(void*, const void*, size_t);
-#else
-Void_t* memset();
-Void_t* memcpy();
-#endif
-#endif
-#endif
-#endif
+#include <string.h>
 
 
 /* Force a value to be in a register and stop the compiler referring
@@ -605,13 +487,9 @@ Void_t* memcpy();
 */
 
 #ifndef MALLOC_FAILURE_ACTION
-#if __STD_C
 #define MALLOC_FAILURE_ACTION \
    errno = ENOMEM;
 
-#else
-#define MALLOC_FAILURE_ACTION
-#endif
 #endif
 
 /*
@@ -619,16 +497,6 @@ Void_t* memcpy();
 */
 
 
-#ifdef LACKS_UNISTD_H
-#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__)
-#if __STD_C
-extern Void_t*     sbrk(ptrdiff_t);
-#else
-extern Void_t*     sbrk();
-#endif
-#endif
-#endif
-
 /*
   MORECORE is the name of the routine to call to obtain more memory
   from the system.  See below for general guidance on writing
@@ -689,49 +557,16 @@ extern Void_t*     sbrk();
 
 
 /*
-  Define HAVE_MMAP as true to optionally make malloc() use mmap() to
-  allocate very large blocks.  These will be returned to the
-  operating system immediately after a free(). Also, if mmap
-  is available, it is used as a backup strategy in cases where
-  MORECORE fails to provide space from system.
-
-  This malloc is best tuned to work with mmap for large requests.
-  If you do not have mmap, operations involving very large chunks (1MB
-  or so) may be slower than you'd like.
-*/
-
-#ifndef HAVE_MMAP
-#define HAVE_MMAP 1
-
-/*
-   Standard unix mmap using /dev/zero clears memory so calloc doesn't
-   need to.
-*/
-
-#ifndef MMAP_CLEARS
-#define MMAP_CLEARS 1
-#endif
-
-#else /* no mmap */
-#ifndef MMAP_CLEARS
-#define MMAP_CLEARS 0
-#endif
-#endif
-
-
-/*
    MMAP_AS_MORECORE_SIZE is the minimum mmap size argument to use if
-   sbrk fails, and mmap is used as a backup (which is done only if
-   HAVE_MMAP).  The value must be a multiple of page size.  This
-   backup strategy generally applies only when systems have "holes" in
-   address space, so sbrk cannot perform contiguous expansion, but
-   there is still space available on system.  On systems for which
-   this is known to be useful (i.e. most linux kernels), this occurs
-   only when programs allocate huge amounts of memory.  Between this,
-   and the fact that mmap regions tend to be limited, the size should
-   be large, to avoid too many mmap calls and thus avoid running out
-   of kernel resources.
-*/
+   sbrk fails, and mmap is used as a backup.  The value must be a
+   multiple of page size.  This backup strategy generally applies only
+   when systems have "holes" in address space, so sbrk cannot perform
+   contiguous expansion, but there is still space available on system.
+   On systems for which this is known to be useful (i.e. most linux
+   kernels), this occurs only when programs allocate huge amounts of
+   memory.  Between this, and the fact that mmap regions tend to be
+   limited, the size should be large, to avoid too many mmap calls and
+   thus avoid running out of kernel resources.  */
 
 #ifndef MMAP_AS_MORECORE_SIZE
 #define MMAP_AS_MORECORE_SIZE (1024 * 1024)
@@ -750,16 +585,7 @@ extern Void_t*     sbrk();
 #define HAVE_MREMAP 0
 #endif
 
-#endif /* HAVE_MMAP */
-
-/* Define USE_ARENAS to enable support for multiple `arenas'.  These
-   are allocated using mmap(), are necessary for threads and
-   occasionally useful to overcome address space limitations affecting
-   sbrk(). */
-
-#ifndef USE_ARENAS
-#define USE_ARENAS HAVE_MMAP
-#endif
+#endif /* HAVE_MREMAP */
 
 
 /*
@@ -776,54 +602,8 @@ extern Void_t*     sbrk();
 
 
 #ifndef malloc_getpagesize
-
-#ifndef LACKS_UNISTD_H
-#  include <unistd.h>
-#endif
-
-#  ifdef _SC_PAGESIZE         /* some SVR4 systems omit an underscore */
-#    ifndef _SC_PAGE_SIZE
-#      define _SC_PAGE_SIZE _SC_PAGESIZE
-#    endif
-#  endif
-
-#  ifdef _SC_PAGE_SIZE
-#    define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
-#  else
-#    if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
-       extern size_t getpagesize();
-#      define malloc_getpagesize getpagesize()
-#    else
-#      ifdef WIN32 /* use supplied emulation of getpagesize */
-#        define malloc_getpagesize getpagesize()
-#      else
-#        ifndef LACKS_SYS_PARAM_H
-#          include <sys/param.h>
-#        endif
-#        ifdef EXEC_PAGESIZE
-#          define malloc_getpagesize EXEC_PAGESIZE
-#        else
-#          ifdef NBPG
-#            ifndef CLSIZE
-#              define malloc_getpagesize NBPG
-#            else
-#              define malloc_getpagesize (NBPG * CLSIZE)
-#            endif
-#          else
-#            ifdef NBPC
-#              define malloc_getpagesize NBPC
-#            else
-#              ifdef PAGESIZE
-#                define malloc_getpagesize PAGESIZE
-#              else /* just guess */
-#                define malloc_getpagesize (4096)
-#              endif
-#            endif
-#          endif
-#        endif
-#      endif
-#    endif
-#  endif
+# include <unistd.h>
+# define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
 #endif
 
 /*
@@ -840,25 +620,8 @@ extern Void_t*     sbrk();
   bunch of fields that are not even meaningful in this version of
   malloc.  These fields are are instead filled by mallinfo() with
   other numbers that might be of interest.
-
-  HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
-  /usr/include/malloc.h file that includes a declaration of struct
-  mallinfo.  If so, it is included; else an SVID2/XPG2 compliant
-  version is declared below.  These must be precisely the same for
-  mallinfo() to work.  The original SVID version of this struct,
-  defined on most systems with mallinfo, declares all fields as
-  ints. But some others define as unsigned long. If your system
-  defines the fields using a type of different width than listed here,
-  you must #include your system version and #define
-  HAVE_USR_INCLUDE_MALLOC_H.
 */
 
-/* #define HAVE_USR_INCLUDE_MALLOC_H */
-
-#ifdef HAVE_USR_INCLUDE_MALLOC_H
-#include "/usr/include/malloc.h"
-#endif
-
 
 /* ---------- description of public routines ------------ */
 
@@ -876,17 +639,11 @@ extern Void_t*     sbrk();
   differs across systems, but is in all cases less than the maximum
   representable value of a size_t.
 */
-#if __STD_C
-Void_t*  public_mALLOc(size_t);
-#else
-Void_t*  public_mALLOc();
-#endif
-#ifdef libc_hidden_proto
+void*  public_mALLOc(size_t);
 libc_hidden_proto (public_mALLOc)
-#endif
 
 /*
-  free(Void_t* p)
+  free(void* p)
   Releases the chunk of memory pointed to by p, that had been previously
   allocated using malloc or a related routine such as realloc.
   It has no effect if p is null. It can have arbitrary (i.e., bad!)
@@ -896,28 +653,18 @@ libc_hidden_proto (public_mALLOc)
   when possible, automatically trigger operations that give
   back unused memory to the system, thus reducing program footprint.
 */
-#if __STD_C
-void     public_fREe(Void_t*);
-#else
-void     public_fREe();
-#endif
-#ifdef libc_hidden_proto
+void     public_fREe(void*);
 libc_hidden_proto (public_fREe)
-#endif
 
 /*
   calloc(size_t n_elements, size_t element_size);
   Returns a pointer to n_elements * element_size bytes, with all locations
   set to zero.
 */
-#if __STD_C
-Void_t*  public_cALLOc(size_t, size_t);
-#else
-Void_t*  public_cALLOc();
-#endif
+void*  public_cALLOc(size_t, size_t);
 
 /*
-  realloc(Void_t* p, size_t n)
+  realloc(void* p, size_t n)
   Returns a pointer to a chunk of size n that contains the same data
   as does chunk p up to the minimum of (n, p's size) bytes, or null
   if no space is available.
@@ -943,14 +690,8 @@ Void_t*  public_cALLOc();
   The old unix realloc convention of allowing the last-free'd chunk
   to be used as an argument to realloc is not supported.
 */
-#if __STD_C
-Void_t*  public_rEALLOc(Void_t*, size_t);
-#else
-Void_t*  public_rEALLOc();
-#endif
-#ifdef libc_hidden_proto
+void*  public_rEALLOc(void*, size_t);
 libc_hidden_proto (public_rEALLOc)
-#endif
 
 /*
   memalign(size_t alignment, size_t n);
@@ -964,25 +705,15 @@ libc_hidden_proto (public_rEALLOc)
 
   Overreliance on memalign is a sure way to fragment space.
 */
-#if __STD_C
-Void_t*  public_mEMALIGn(size_t, size_t);
-#else
-Void_t*  public_mEMALIGn();
-#endif
-#ifdef libc_hidden_proto
+void*  public_mEMALIGn(size_t, size_t);
 libc_hidden_proto (public_mEMALIGn)
-#endif
 
 /*
   valloc(size_t n);
   Equivalent to memalign(pagesize, n), where pagesize is the page
   size of the system. If the pagesize is unknown, 4096 is used.
 */
-#if __STD_C
-Void_t*  public_vALLOc(size_t);
-#else
-Void_t*  public_vALLOc();
-#endif
+void*  public_vALLOc(size_t);
 
 
 
@@ -1007,11 +738,7 @@ Void_t*  public_vALLOc();
   M_MMAP_THRESHOLD -3         128*1024   any   (or 0 if no MMAP support)
   M_MMAP_MAX       -4         65536      any   (0 disables use of mmap)
 */
-#if __STD_C
 int      public_mALLOPt(int, int);
-#else
-int      public_mALLOPt();
-#endif
 
 
 /*
@@ -1037,137 +764,7 @@ int      public_mALLOPt();
   be kept as longs, the reported values may wrap around zero and
   thus be inaccurate.
 */
-#if __STD_C
 struct mallinfo public_mALLINFo(void);
-#else
-struct mallinfo public_mALLINFo();
-#endif
-
-#ifndef _LIBC
-/*
-  independent_calloc(size_t n_elements, size_t element_size, Void_t* chunks[]);
-
-  independent_calloc is similar to calloc, but instead of returning a
-  single cleared space, it returns an array of pointers to n_elements
-  independent elements that can hold contents of size elem_size, each
-  of which starts out cleared, and can be independently freed,
-  realloc'ed etc. The elements are guaranteed to be adjacently
-  allocated (this is not guaranteed to occur with multiple callocs or
-  mallocs), which may also improve cache locality in some
-  applications.
-
-  The "chunks" argument is optional (i.e., may be null, which is
-  probably the most typical usage). If it is null, the returned array
-  is itself dynamically allocated and should also be freed when it is
-  no longer needed. Otherwise, the chunks array must be of at least
-  n_elements in length. It is filled in with the pointers to the
-  chunks.
-
-  In either case, independent_calloc returns this pointer array, or
-  null if the allocation failed.  If n_elements is zero and "chunks"
-  is null, it returns a chunk representing an array with zero elements
-  (which should be freed if not wanted).
-
-  Each element must be individually freed when it is no longer
-  needed. If you'd like to instead be able to free all at once, you
-  should instead use regular calloc and assign pointers into this
-  space to represent elements.  (In this case though, you cannot
-  independently free elements.)
-
-  independent_calloc simplifies and speeds up implementations of many
-  kinds of pools.  It may also be useful when constructing large data
-  structures that initially have a fixed number of fixed-sized nodes,
-  but the number is not known at compile time, and some of the nodes
-  may later need to be freed. For example:
-
-  struct Node { int item; struct Node* next; };
-
-  struct Node* build_list() {
-    struct Node** pool;
-    int n = read_number_of_nodes_needed();
-    if (n <= 0) return 0;
-    pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0);
-    if (pool == 0) die();
-    // organize into a linked list...
-    struct Node* first = pool[0];
-    for (i = 0; i < n-1; ++i)
-      pool[i]->next = pool[i+1];
-    free(pool);     // Can now free the array (or not, if it is needed later)
-    return first;
-  }
-*/
-#if __STD_C
-Void_t** public_iCALLOc(size_t, size_t, Void_t**);
-#else
-Void_t** public_iCALLOc();
-#endif
-
-/*
-  independent_comalloc(size_t n_elements, size_t sizes[], Void_t* chunks[]);
-
-  independent_comalloc allocates, all at once, a set of n_elements
-  chunks with sizes indicated in the "sizes" array.    It returns
-  an array of pointers to these elements, each of which can be
-  independently freed, realloc'ed etc. The elements are guaranteed to
-  be adjacently allocated (this is not guaranteed to occur with
-  multiple callocs or mallocs), which may also improve cache locality
-  in some applications.
-
-  The "chunks" argument is optional (i.e., may be null). If it is null
-  the returned array is itself dynamically allocated and should also
-  be freed when it is no longer needed. Otherwise, the chunks array
-  must be of at least n_elements in length. It is filled in with the
-  pointers to the chunks.
-
-  In either case, independent_comalloc returns this pointer array, or
-  null if the allocation failed.  If n_elements is zero and chunks is
-  null, it returns a chunk representing an array with zero elements
-  (which should be freed if not wanted).
-
-  Each element must be individually freed when it is no longer
-  needed. If you'd like to instead be able to free all at once, you
-  should instead use a single regular malloc, and assign pointers at
-  particular offsets in the aggregate space. (In this case though, you
-  cannot independently free elements.)
-
-  independent_comallac differs from independent_calloc in that each
-  element may have a different size, and also that it does not
-  automatically clear elements.
-
-  independent_comalloc can be used to speed up allocation in cases
-  where several structs or objects must always be allocated at the
-  same time.  For example:
-
-  struct Head { ... }
-  struct Foot { ... }
-
-  void send_message(char* msg) {
-    int msglen = strlen(msg);
-    size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) };
-    void* chunks[3];
-    if (independent_comalloc(3, sizes, chunks) == 0)
-      die();
-    struct Head* head = (struct Head*)(chunks[0]);
-    char*        body = (char*)(chunks[1]);
-    struct Foot* foot = (struct Foot*)(chunks[2]);
-    // ...
-  }
-
-  In general though, independent_comalloc is worth using only for
-  larger values of n_elements. For small values, you probably won't
-  detect enough difference from series of malloc calls to bother.
-
-  Overuse of independent_comalloc can increase overall memory usage,
-  since it cannot reuse existing noncontiguous small chunks that
-  might be available for some of the elements.
-*/
-#if __STD_C
-Void_t** public_iCOMALLOc(size_t, size_t*, Void_t**);
-#else
-Void_t** public_iCOMALLOc();
-#endif
-
-#endif /* _LIBC */
 
 
 /*
@@ -1175,25 +772,17 @@ Void_t** public_iCOMALLOc();
   Equivalent to valloc(minimum-page-that-holds(n)), that is,
   round up n to nearest pagesize.
  */
-#if __STD_C
-Void_t*  public_pVALLOc(size_t);
-#else
-Void_t*  public_pVALLOc();
-#endif
+void*  public_pVALLOc(size_t);
 
 /*
-  cfree(Void_t* p);
+  cfree(void* p);
   Equivalent to free(p).
 
   cfree is needed/defined on some systems that pair it with calloc,
   for odd historical reasons (such as: cfree is used in example
   code in the first edition of K&R).
 */
-#if __STD_C
-void     public_cFREe(Void_t*);
-#else
-void     public_cFREe();
-#endif
+void     public_cFREe(void*);
 
 /*
   malloc_trim(size_t pad);
@@ -1219,14 +808,10 @@ void     public_cFREe();
   On systems that do not support "negative sbrks", it will always
   return 0.
 */
-#if __STD_C
 int      public_mTRIm(size_t);
-#else
-int      public_mTRIm();
-#endif
 
 /*
-  malloc_usable_size(Void_t* p);
+  malloc_usable_size(void* p);
 
   Returns the number of bytes you can actually use in
   an allocated chunk, which may be more than you requested (although
@@ -1240,11 +825,7 @@ int      public_mTRIm();
   assert(malloc_usable_size(p) >= 256);
 
 */
-#if __STD_C
-size_t   p