1Tcl_Alloc(3)                Tcl Library Procedures                Tcl_Alloc(3)
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NAME

8       Tcl_Alloc, Tcl_Free, Tcl_Realloc, Tcl_AttemptAlloc, Tcl_AttemptRealloc,
9       ckalloc, ckfree, ckrealloc, attemptckalloc, attemptckrealloc - allocate
10       or free heap memory
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SYNOPSIS

13       #include <tcl.h>
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15       char *
16       Tcl_Alloc(size)
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18       void
19       Tcl_Free(ptr)
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21       char *
22       Tcl_Realloc(ptr, size)
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24       char *
25       Tcl_AttemptAlloc(size)
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27       char *
28       Tcl_AttemptRealloc(ptr, size)
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30       char *
31       ckalloc(size)
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33       void
34       ckfree(ptr)
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36       char *
37       ckrealloc(ptr, size)
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39       char *
40       attemptckalloc(size)
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42       char *
43       attemptckrealloc(ptr, size)
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ARGUMENTS

46       int    size    (in)      Size in bytes of the memory block to allocate.
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48       char   *ptr    (in)      Pointer to memory block to free or realloc.
49_________________________________________________________________
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DESCRIPTION

53       These  procedures provide a platform and compiler independent interface
54       for memory allocation.  Programs that need  to  transfer  ownership  of
55       memory  blocks  between Tcl and other modules should use these routines
56       rather than the native malloc() and free() routines provided by  the  C
57       run-time library.
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59       Tcl_Alloc  returns a pointer to a block of at least size bytes suitably
60       aligned for any use.
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62       Tcl_Free makes the space referred to by ptr available for further allo‐
63       cation.
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65       Tcl_Realloc  changes  the  size  of the block pointed to by ptr to size
66       bytes and returns a pointer to the new block.   The  contents  will  be
67       unchanged  up  to  the  lesser  of the new and old sizes.  The returned
68       location may be different from ptr.
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70       Tcl_AttemptAlloc and Tcl_AttemptRealloc are identical  in  function  to
71       Tcl_Alloc   and   Tcl_Realloc,   except   that   Tcl_AttemptAlloc   and
72       Tcl_AttemptRealloc will not cause the Tcl interpreter to panic  if  the
73       memory allocation fails.  If the allocation fails, these functions will
74       return NULL.  Note that on some platforms,  attempting  to  allocate  a
75       block of memory will also cause these functions to return NULL.
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77       The   procedures   ckalloc,   ckfree,  ckrealloc,  attemptckalloc,  and
78       attemptckrealloc are implemented as macros.  Normally,  they  are  syn‐
79       onyms  for  the corresponding procedures documented on this page.  When
80       Tcl and  all  modules  calling  Tcl  are  compiled  with  TCL_MEM_DEBUG
81       defined,  however,  these  macros are redefined to be special debugging
82       versions of of these procedures.  To  support  Tcl's  memory  debugging
83       within  a module, use the macros rather than direct calls to Tcl_Alloc,
84       etc.
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KEYWORDS

88       alloc, allocation, free, malloc, memory, realloc, TCL_MEM_DEBUG
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92Tcl                                   7.5                         Tcl_Alloc(3)