NAME

       Tcl_Alloc, Tcl_Free, Tcl_Realloc, Tcl_AttemptAlloc, Tcl_AttemptRealloc, Tcl_GetMemoryInfo,
       ckalloc, ckfree, ckrealloc, attemptckalloc,  attemptckrealloc  -  allocate  or  free  heap
       memory

SYNOPSIS

       #include <tcl.h>

       char *
       Tcl_Alloc(size)

       void
       Tcl_Free(ptr)

       char *
       Tcl_Realloc(ptr, size)

       char *
       Tcl_AttemptAlloc(size)

       char *
       Tcl_AttemptRealloc(ptr, size)

       void
       Tcl_GetMemoryInfo(dsPtr)

       char *
       ckalloc(size)

       void
       ckfree(ptr)

       char *
       ckrealloc(ptr, size)

       char *
       attemptckalloc(size)

       char *
       attemptckrealloc(ptr, size)

ARGUMENTS

       unsigned int size (in)   Size in bytes of the memory block to allocate.

       char *ptr (in)           Pointer to memory block to free or realloc.

       Tcl_DString *dsPtr (in)  Initialized DString pointer.
_________________________________________________________________________________________________

DESCRIPTION

       These  procedures  provide  a  platform  and  compiler  independent  interface  for memory
       allocation.  Programs that need to transfer ownership of memory  blocks  between  Tcl  and
       other  modules  should  use  these  routines  rather  than  the native malloc() and free()
       routines provided by the C run-time library.

       Tcl_Alloc returns a pointer to a block of at least size bytes  suitably  aligned  for  any
       use.

       Tcl_Free makes the space referred to by ptr available for further allocation.

       Tcl_Realloc  changes  the  size of the block pointed to by ptr to size bytes and returns a
       pointer to the new block.  The contents will be unchanged up to the lesser of the new  and
       old  sizes.   The  returned  location  may be different from ptr.  If ptr is NULL, this is
       equivalent to calling Tcl_Alloc with just the size argument.

       Tcl_AttemptAlloc and  Tcl_AttemptRealloc  are  identical  in  function  to  Tcl_Alloc  and
       Tcl_Realloc,  except  that  Tcl_AttemptAlloc and Tcl_AttemptRealloc will not cause the Tcl
       interpreter to panic if the memory allocation  fails.   If  the  allocation  fails,  these
       functions  will  return  NULL.   Note  that  on some platforms, but not all, attempting to
       allocate a zero-sized block of memory will also cause these functions to return NULL.

       The procedures  ckalloc,  ckfree,  ckrealloc,  attemptckalloc,  and  attemptckrealloc  are
       implemented  as  macros.   Normally,  they  are  synonyms for the corresponding procedures
       documented on this page.   When  Tcl  and  all  modules  calling  Tcl  are  compiled  with
       TCL_MEM_DEBUG  defined,  however,  these  macros  are  redefined  to  be special debugging
       versions of these procedures.  To support Tcl's memory debugging within a module, use  the
       macros rather than direct calls to Tcl_Alloc, etc.

       Tcl_GetMemoryInfo  appends  a  list-of-lists of memory stats to the provided DString. This
       function cannot be used in stub-enabled extensions, and it is only  available  if  Tcl  is
       compiled with the threaded memory allocator.

KEYWORDS

       alloc, allocation, free, malloc, memory, realloc, TCL_MEM_DEBUG