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       unsigned 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.  If ptr is NULL, this is equivalent
69       to calling Tcl_Alloc with just the size argument.
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71       Tcl_AttemptAlloc  and  Tcl_AttemptRealloc  are identical in function to
72       Tcl_Alloc   and   Tcl_Realloc,   except   that   Tcl_AttemptAlloc   and
73       Tcl_AttemptRealloc  will  not cause the Tcl interpreter to panic if the
74       memory allocation fails.  If the allocation fails, these functions will
75       return  NULL.   Note that on some platforms, but not all, attempting to
76       allocate a zero-sized block of memory will also cause  these  functions
77       to return NULL.
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79       The   procedures   ckalloc,   ckfree,  ckrealloc,  attemptckalloc,  and
80       attemptckrealloc are implemented as macros.  Normally,  they  are  syn‐
81       onyms  for  the corresponding procedures documented on this page.  When
82       Tcl and  all  modules  calling  Tcl  are  compiled  with  TCL_MEM_DEBUG
83       defined,  however,  these  macros are redefined to be special debugging
84       versions of these procedures.  To support Tcl's memory debugging within
85       a module, use the macros rather than direct calls to Tcl_Alloc, etc.
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KEYWORDS

89       alloc, allocation, free, malloc, memory, realloc, TCL_MEM_DEBUG
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93Tcl                                   7.5                         Tcl_Alloc(3)