NAME

       Tcl_Alloc,  Tcl_Free,  Tcl_Realloc, Tcl_AttemptAlloc, Tcl_AttemptRealloc, 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)

       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.
_________________________________________________________________

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.

KEYWORDS

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