Tcl_Alloc(3tcl) Tcl Library Procedures Tcl_Alloc(3tcl)
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NAME
Tcl_Alloc, Tcl_Free, Tcl_Realloc, Tcl_AttemptAlloc, Tcl_AttemptRealloc,
Tcl_GetMemoryInfo, ckalloc, ckfree, ckrealloc, attemptckalloc, at-
temptckrealloc - 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.
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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 allo-
cation.
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 un-
changed up to the lesser of the new and old sizes. The returned loca-
tion 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_At-
temptRealloc 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 at-
temptckrealloc 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, how-
ever, 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 pro-
vided 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
Tcl 7.5 Tcl_Alloc(3tcl)
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