TclAlloc(3)                Tcl Library Procedures                TclAlloc(3)





NAME
       TclAlloc, TclFree, TclRealloc, TclAttemptAlloc, TclAttemptRealloc,
       ckalloc, ckfree, ckrealloc, attemptckalloc, attemptckrealloc - allocate
       or free heap memory

SYNOPSIS
       ##include <>

       char *
       TclAlloc(size)

       void
       TclFree(ptr)

       char *
       TclRealloc(ptr, size)

       char *
       TclAttemptAlloc(size)

       char *
       TclAttemptRealloc(ptr, size)

       char *
       ckalloc(size)

       void
       ckfree(ptr)

       char *
       ckrealloc(ptr, size)

       char *
       attemptckalloc(size)

       char *
       attemptckrealloc(ptr, size)

ARGUMENTS
       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.

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

       TclFree makes the space referred to by ptr available for further allo-
       cation.

       TclRealloc 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.

       TclAttemptAlloc  and  TclAttemptRealloc  are identical in function to
       TclAlloc   and   TclRealloc,   except   that   TclAttemptAlloc   and
       TclAttemptRealloc  will  not cause the Tcl interpreter to panic if the
       memory allocation fails.  If the allocation fails, these functions will
       return  NUL.   Note  that  on some platforms, attempting to allocate a
       block of memory will also cause these functions to return NUL.

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


KEYWORDS
       alloc, allocation, free, malloc, memory, realloc, TCLMEMDEBUG



Tcl                                   7.5                         TclAlloc(3)