Tcl_Alloc(3) Tcl Library Procedures Tcl_Alloc(3)

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NAME

Tcl_Alloc, Tcl_Free, Tcl_Realloc, Tcl_AttemptAlloc,
Tcl_AttemptRealloc, Tcl_GetMemoryInfo, 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)

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
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.

Tcl_GetMemoryInfo appends a list-of-lists of memory stats to the
provided 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(3)