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