7 The most current version of this document is available at
8 http://samba.org/ftp/unpacked/samba4/source/lib/talloc/talloc_guide.txt
10 If you are used to the "old" talloc from Samba3 before 3.0.20 then please read
11 this carefully, as talloc has changed a lot. With 3.0.20 (or 3.0.14?) the
12 Samba4 talloc has been ported back to Samba3, so this guide applies to both.
14 The new talloc is a hierarchical, reference counted memory pool system
15 with destructors. Quite a mouthful really, but not too bad once you
18 Perhaps the biggest change from Samba3 is that there is no distinction
19 between a "talloc context" and a "talloc pointer". Any pointer
20 returned from talloc() is itself a valid talloc context. This means
23 struct foo *X = talloc(mem_ctx, struct foo);
24 X->name = talloc_strdup(X, "foo");
26 and the pointer X->name would be a "child" of the talloc context "X"
27 which is itself a child of mem_ctx. So if you do talloc_free(mem_ctx)
28 then it is all destroyed, whereas if you do talloc_free(X) then just X
29 and X->name are destroyed, and if you do talloc_free(X->name) then
30 just the name element of X is destroyed.
32 If you think about this, then what this effectively gives you is an
33 n-ary tree, where you can free any part of the tree with
36 If you find this confusing, then I suggest you run the testsuite to
37 watch talloc in action. You may also like to add your own tests to
38 testsuite.c to clarify how some particular situation is handled.
44 All the additional features of talloc() over malloc() do come at a
45 price. We have a simple performance test in Samba4 that measures
46 talloc() versus malloc() performance, and it seems that talloc() is
47 about 4% slower than malloc() on my x86 Debian Linux box. For Samba,
48 the great reduction in code complexity that we get by using talloc
49 makes this worthwhile, especially as the total overhead of
50 talloc/malloc in Samba is already quite small.
56 The following is a complete guide to the talloc API. Read it all at
62 talloc itself does not deal with threads. It is thread-safe (assuming
63 the underlying "malloc" is), as long as each thread uses different
65 If two threads uses the same context then they need to synchronize in
66 order to be safe. In particular:
67 - when using talloc_enable_leak_report(), giving directly NULL as a
68 parent context implicitly refers to a hidden "null context" global
69 variable, so this should not be used in a multi-threaded environment
70 without proper synchronization ;
71 - the context returned by talloc_autofree_context() is also global so
72 shouldn't be used by several threads simultaneously without
76 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
77 (type *)talloc(const void *context, type);
79 The talloc() macro is the core of the talloc library. It takes a
80 memory context and a type, and returns a pointer to a new area of
81 memory of the given type.
83 The returned pointer is itself a talloc context, so you can use it as
84 the context argument to more calls to talloc if you wish.
86 The returned pointer is a "child" of the supplied context. This means
87 that if you talloc_free() the context then the new child disappears as
88 well. Alternatively you can free just the child.
90 The context argument to talloc() can be NULL, in which case a new top
91 level context is created.
94 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
95 void *talloc_size(const void *context, size_t size);
97 The function talloc_size() should be used when you don't have a
98 convenient type to pass to talloc(). Unlike talloc(), it is not type
99 safe (as it returns a void *), so you are on your own for type checking.
101 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
102 (typeof(ptr)) talloc_ptrtype(const void *ctx, ptr);
104 The talloc_ptrtype() macro should be used when you have a pointer and
105 want to allocate memory to point at with this pointer. When compiling
106 with gcc >= 3 it is typesafe. Note this is a wrapper of talloc_size()
107 and talloc_get_name() will return the current location in the source file.
110 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
111 int talloc_free(void *ptr);
113 The talloc_free() function frees a piece of talloc memory, and all its
114 children. You can call talloc_free() on any pointer returned by
117 The return value of talloc_free() indicates success or failure, with 0
118 returned for success and -1 for failure. The only possible failure
119 condition is if the pointer had a destructor attached to it and the
120 destructor returned -1. See talloc_set_destructor() for details on
123 If this pointer has an additional parent when talloc_free() is called
124 then the memory is not actually released, but instead the most
125 recently established parent is destroyed. See talloc_reference() for
126 details on establishing additional parents.
128 For more control on which parent is removed, see talloc_unlink()
130 talloc_free() operates recursively on its children.
133 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
134 int talloc_free_children(void *ptr);
136 The talloc_free_children() walks along the list of all children of a
137 talloc context and talloc_free()s only the children, not the context
141 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
142 void *talloc_reference(const void *context, const void *ptr);
144 The talloc_reference() function makes "context" an additional parent
147 The return value of talloc_reference() is always the original pointer
148 "ptr", unless talloc ran out of memory in creating the reference in
149 which case it will return NULL (each additional reference consumes
150 around 48 bytes of memory on intel x86 platforms).
152 If "ptr" is NULL, then the function is a no-op, and simply returns NULL.
154 After creating a reference you can free it in one of the following
157 - you can talloc_free() any parent of the original pointer. That
158 will reduce the number of parents of this pointer by 1, and will
159 cause this pointer to be freed if it runs out of parents.
161 - you can talloc_free() the pointer itself. That will destroy the
162 most recently established parent to the pointer and leave the
163 pointer as a child of its current parent.
165 For more control on which parent to remove, see talloc_unlink()
168 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
169 int talloc_unlink(const void *context, const void *ptr);
171 The talloc_unlink() function removes a specific parent from ptr. The
172 context passed must either be a context used in talloc_reference()
173 with this pointer, or must be a direct parent of ptr.
175 Note that if the parent has already been removed using talloc_free()
176 then this function will fail and will return -1. Likewise, if "ptr"
177 is NULL, then the function will make no modifications and return -1.
179 Usually you can just use talloc_free() instead of talloc_unlink(), but
180 sometimes it is useful to have the additional control on which parent
184 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
185 void talloc_set_destructor(const void *ptr, int (*destructor)(void *));
187 The function talloc_set_destructor() sets the "destructor" for the
188 pointer "ptr". A destructor is a function that is called when the
189 memory used by a pointer is about to be released. The destructor
190 receives the pointer as an argument, and should return 0 for success
193 The destructor can do anything it wants to, including freeing other
194 pieces of memory. A common use for destructors is to clean up
195 operating system resources (such as open file descriptors) contained
196 in the structure the destructor is placed on.
198 You can only place one destructor on a pointer. If you need more than
199 one destructor then you can create a zero-length child of the pointer
200 and place an additional destructor on that.
202 To remove a destructor call talloc_set_destructor() with NULL for the
205 If your destructor attempts to talloc_free() the pointer that it is
206 the destructor for then talloc_free() will return -1 and the free will
207 be ignored. This would be a pointless operation anyway, as the
208 destructor is only called when the memory is just about to go away.
211 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
212 int talloc_increase_ref_count(const void *ptr);
214 The talloc_increase_ref_count(ptr) function is exactly equivalent to:
216 talloc_reference(NULL, ptr);
218 You can use either syntax, depending on which you think is clearer in
221 It returns 0 on success and -1 on failure.
223 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
224 size_t talloc_reference_count(const void *ptr);
226 Return the number of references to the pointer.
228 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
229 void talloc_set_name(const void *ptr, const char *fmt, ...);
231 Each talloc pointer has a "name". The name is used principally for
232 debugging purposes, although it is also possible to set and get the
233 name on a pointer in as a way of "marking" pointers in your code.
235 The main use for names on pointer is for "talloc reports". See
236 talloc_report() and talloc_report_full() for details. Also see
237 talloc_enable_leak_report() and talloc_enable_leak_report_full().
239 The talloc_set_name() function allocates memory as a child of the
240 pointer. It is logically equivalent to:
241 talloc_set_name_const(ptr, talloc_asprintf(ptr, fmt, ...));
243 Note that multiple calls to talloc_set_name() will allocate more
244 memory without releasing the name. All of the memory is released when
245 the ptr is freed using talloc_free().
248 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
249 void talloc_set_name_const(const void *ptr, const char *name);
251 The function talloc_set_name_const() is just like talloc_set_name(),
252 but it takes a string constant, and is much faster. It is extensively
253 used by the "auto naming" macros, such as talloc_p().
255 This function does not allocate any memory. It just copies the
256 supplied pointer into the internal representation of the talloc
257 ptr. This means you must not pass a name pointer to memory that will
258 disappear before the ptr is freed with talloc_free().
261 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
262 void *talloc_named(const void *context, size_t size, const char *fmt, ...);
264 The talloc_named() function creates a named talloc pointer. It is
267 ptr = talloc_size(context, size);
268 talloc_set_name(ptr, fmt, ....);
271 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
272 void *talloc_named_const(const void *context, size_t size, const char *name);
274 This is equivalent to:
276 ptr = talloc_size(context, size);
277 talloc_set_name_const(ptr, name);
280 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
281 const char *talloc_get_name(const void *ptr);
283 This returns the current name for the given talloc pointer. See
284 talloc_set_name() for details.
287 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
288 void *talloc_init(const char *fmt, ...);
290 This function creates a zero length named talloc context as a top
291 level context. It is equivalent to:
293 talloc_named(NULL, 0, fmt, ...);
296 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
297 void *talloc_new(void *ctx);
299 This is a utility macro that creates a new memory context hanging
300 off an exiting context, automatically naming it "talloc_new: __location__"
301 where __location__ is the source line it is called from. It is
302 particularly useful for creating a new temporary working context.
305 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
306 (type *)talloc_realloc(const void *context, void *ptr, type, count);
308 The talloc_realloc() macro changes the size of a talloc
309 pointer. The "count" argument is the number of elements of type "type"
310 that you want the resulting pointer to hold.
312 talloc_realloc() has the following equivalences:
314 talloc_realloc(context, NULL, type, 1) ==> talloc(context, type);
315 talloc_realloc(context, NULL, type, N) ==> talloc_array(context, type, N);
316 talloc_realloc(context, ptr, type, 0) ==> talloc_free(ptr);
318 The "context" argument is only used if "ptr" is NULL, otherwise it is
321 talloc_realloc() returns the new pointer, or NULL on failure. The call
322 will fail either due to a lack of memory, or because the pointer has
323 more than one parent (see talloc_reference()).
326 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
327 void *talloc_realloc_size(const void *context, void *ptr, size_t size);
329 the talloc_realloc_size() function is useful when the type is not
330 known so the typesafe talloc_realloc() cannot be used.
333 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
334 void *talloc_steal(const void *new_ctx, const void *ptr);
336 The talloc_steal() function changes the parent context of a talloc
337 pointer. It is typically used when the context that the pointer is
338 currently a child of is going to be freed and you wish to keep the
339 memory for a longer time.
341 The talloc_steal() function returns the pointer that you pass it. It
342 does not have any failure modes.
344 NOTE: It is possible to produce loops in the parent/child relationship
345 if you are not careful with talloc_steal(). No guarantees are provided
346 as to your sanity or the safety of your data if you do this.
348 talloc_steal (new_ctx, NULL) will return NULL with no sideeffects.
350 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
351 size_t talloc_total_size(const void *ptr);
353 The talloc_total_size() function returns the total size in bytes used
354 by this pointer and all child pointers. Mostly useful for debugging.
356 Passing NULL is allowed, but it will only give a meaningful result if
357 talloc_enable_leak_report() or talloc_enable_leak_report_full() has
361 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
362 size_t talloc_total_blocks(const void *ptr);
364 The talloc_total_blocks() function returns the total memory block
365 count used by this pointer and all child pointers. Mostly useful for
368 Passing NULL is allowed, but it will only give a meaningful result if
369 talloc_enable_leak_report() or talloc_enable_leak_report_full() has
372 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
373 void talloc_report_depth_cb(const void *ptr, int depth, int max_depth,
374 void (*callback)(const void *ptr,
375 int depth, int max_depth,
380 This provides a more flexible reports than talloc_report(). It
381 will recursively call the callback for the entire tree of memory
382 referenced by the pointer. References in the tree are passed with
383 is_ref = 1 and the pointer that is referenced.
385 You can pass NULL for the pointer, in which case a report is
386 printed for the top level memory context, but only if
387 talloc_enable_leak_report() or talloc_enable_leak_report_full()
390 The recursion is stopped when depth >= max_depth.
391 max_depth = -1 means only stop at leaf nodes.
394 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
395 void talloc_report_depth_file(const void *ptr, int depth, int max_depth, FILE *f);
397 This provides a more flexible reports than talloc_report(). It
398 will let you specify the depth and max_depth.
401 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
402 void talloc_report(const void *ptr, FILE *f);
404 The talloc_report() function prints a summary report of all memory
405 used by ptr. One line of report is printed for each immediate child of
406 ptr, showing the total memory and number of blocks used by that child.
408 You can pass NULL for the pointer, in which case a report is printed
409 for the top level memory context, but only if
410 talloc_enable_leak_report() or talloc_enable_leak_report_full() has
414 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
415 void talloc_report_full(const void *ptr, FILE *f);
417 This provides a more detailed report than talloc_report(). It will
418 recursively print the ensire tree of memory referenced by the
419 pointer. References in the tree are shown by giving the name of the
420 pointer that is referenced.
422 You can pass NULL for the pointer, in which case a report is printed
423 for the top level memory context, but only if
424 talloc_enable_leak_report() or talloc_enable_leak_report_full() has
428 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
429 void talloc_enable_leak_report(void);
431 This enables calling of talloc_report(NULL, stderr) when the program
432 exits. In Samba4 this is enabled by using the --leak-report command
435 For it to be useful, this function must be called before any other
436 talloc function as it establishes a "null context" that acts as the
437 top of the tree. If you don't call this function first then passing
438 NULL to talloc_report() or talloc_report_full() won't give you the
441 Here is a typical talloc report:
443 talloc report on 'null_context' (total 267 bytes in 15 blocks)
444 libcli/auth/spnego_parse.c:55 contains 31 bytes in 2 blocks
445 libcli/auth/spnego_parse.c:55 contains 31 bytes in 2 blocks
446 iconv(UTF8,CP850) contains 42 bytes in 2 blocks
447 libcli/auth/spnego_parse.c:55 contains 31 bytes in 2 blocks
448 iconv(CP850,UTF8) contains 42 bytes in 2 blocks
449 iconv(UTF8,UTF-16LE) contains 45 bytes in 2 blocks
450 iconv(UTF-16LE,UTF8) contains 45 bytes in 2 blocks
453 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
454 void talloc_enable_leak_report_full(void);
456 This enables calling of talloc_report_full(NULL, stderr) when the
457 program exits. In Samba4 this is enabled by using the
458 --leak-report-full command line option.
460 For it to be useful, this function must be called before any other
461 talloc function as it establishes a "null context" that acts as the
462 top of the tree. If you don't call this function first then passing
463 NULL to talloc_report() or talloc_report_full() won't give you the
466 Here is a typical full report:
468 full talloc report on 'root' (total 18 bytes in 8 blocks)
469 p1 contains 18 bytes in 7 blocks (ref 0)
470 r1 contains 13 bytes in 2 blocks (ref 0)
472 p2 contains 1 bytes in 1 blocks (ref 1)
473 x3 contains 1 bytes in 1 blocks (ref 0)
474 x2 contains 1 bytes in 1 blocks (ref 0)
475 x1 contains 1 bytes in 1 blocks (ref 0)
478 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
479 void talloc_enable_null_tracking(void);
481 This enables tracking of the NULL memory context without enabling leak
482 reporting on exit. Useful for when you want to do your own leak
483 reporting call via talloc_report_null_full();
485 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
486 void talloc_disable_null_tracking(void);
488 This disables tracking of the NULL memory context.
490 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
491 (type *)talloc_zero(const void *ctx, type);
493 The talloc_zero() macro is equivalent to:
495 ptr = talloc(ctx, type);
496 if (ptr) memset(ptr, 0, sizeof(type));
499 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
500 void *talloc_zero_size(const void *ctx, size_t size)
502 The talloc_zero_size() function is useful when you don't have a known type
505 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
506 void *talloc_memdup(const void *ctx, const void *p, size_t size);
508 The talloc_memdup() function is equivalent to:
510 ptr = talloc_size(ctx, size);
511 if (ptr) memcpy(ptr, p, size);
514 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
515 char *talloc_strdup(const void *ctx, const char *p);
517 The talloc_strdup() function is equivalent to:
519 ptr = talloc_size(ctx, strlen(p)+1);
520 if (ptr) memcpy(ptr, p, strlen(p)+1);
522 This functions sets the name of the new pointer to the passed
523 string. This is equivalent to:
524 talloc_set_name_const(ptr, ptr)
526 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
527 char *talloc_strndup(const void *t, const char *p, size_t n);
529 The talloc_strndup() function is the talloc equivalent of the C
530 library function strndup()
532 This functions sets the name of the new pointer to the passed
533 string. This is equivalent to:
534 talloc_set_name_const(ptr, ptr)
536 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
537 char *talloc_append_string(const void *t, char *orig, const char *append);
539 The talloc_append_string() function appends the given formatted
540 string to the given string.
542 This function sets the name of the new pointer to the new
543 string. This is equivalent to:
544 talloc_set_name_const(ptr, ptr)
546 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
547 char *talloc_vasprintf(const void *t, const char *fmt, va_list ap);
549 The talloc_vasprintf() function is the talloc equivalent of the C
550 library function vasprintf()
552 This functions sets the name of the new pointer to the new
553 string. This is equivalent to:
554 talloc_set_name_const(ptr, ptr)
557 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
558 char *talloc_asprintf(const void *t, const char *fmt, ...);
560 The talloc_asprintf() function is the talloc equivalent of the C
561 library function asprintf()
563 This functions sets the name of the new pointer to the new
564 string. This is equivalent to:
565 talloc_set_name_const(ptr, ptr)
568 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
569 char *talloc_asprintf_append(char *s, const char *fmt, ...);
571 The talloc_asprintf_append() function appends the given formatted
572 string to the given string.
574 This functions sets the name of the new pointer to the new
575 string. This is equivalent to:
576 talloc_set_name_const(ptr, ptr)
579 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
580 (type *)talloc_array(const void *ctx, type, uint_t count);
582 The talloc_array() macro is equivalent to:
584 (type *)talloc_size(ctx, sizeof(type) * count);
586 except that it provides integer overflow protection for the multiply,
587 returning NULL if the multiply overflows.
590 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
591 void *talloc_array_size(const void *ctx, size_t size, uint_t count);
593 The talloc_array_size() function is useful when the type is not
594 known. It operates in the same way as talloc_array(), but takes a size
597 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
598 (typeof(ptr)) talloc_array_ptrtype(const void *ctx, ptr, uint_t count);
600 The talloc_ptrtype() macro should be used when you have a pointer to an array
601 and want to allocate memory of an array to point at with this pointer. When compiling
602 with gcc >= 3 it is typesafe. Note this is a wrapper of talloc_array_size()
603 and talloc_get_name() will return the current location in the source file.
606 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
607 void *talloc_realloc_fn(const void *ctx, void *ptr, size_t size);
609 This is a non-macro version of talloc_realloc(), which is useful
610 as libraries sometimes want a ralloc function pointer. A realloc()
611 implementation encapsulates the functionality of malloc(), free() and
612 realloc() in one call, which is why it is useful to be able to pass
613 around a single function pointer.
616 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
617 void *talloc_autofree_context(void);
619 This is a handy utility function that returns a talloc context
620 which will be automatically freed on program exit. This can be used
621 to reduce the noise in memory leak reports.
624 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
625 void *talloc_check_name(const void *ptr, const char *name);
627 This function checks if a pointer has the specified name. If it does
628 then the pointer is returned. It it doesn't then NULL is returned.
631 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
632 (type *)talloc_get_type(const void *ptr, type);
634 This macro allows you to do type checking on talloc pointers. It is
635 particularly useful for void* private pointers. It is equivalent to
638 (type *)talloc_check_name(ptr, #type)
641 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
642 talloc_set_type(const void *ptr, type);
644 This macro allows you to force the name of a pointer to be a
645 particular type. This can be used in conjunction with
646 talloc_get_type() to do type checking on void* pointers.
648 It is equivalent to this:
649 talloc_set_name_const(ptr, #type)
651 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
652 talloc_get_size(const void *ctx);
654 This function lets you know the amount of memory alloced so far by
655 this context. It does NOT account for subcontext memory.
656 This can be used to calculate the size of an array.
658 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
659 void *talloc_find_parent_byname(const void *ctx, const char *name);
661 Find a parent memory context of the current context that has the given
662 name. This can be very useful in complex programs where it may be
663 difficult to pass all information down to the level you need, but you
664 know the structure you want is a parent of another context.
666 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
667 (type *)talloc_find_parent_bytype(ctx, type);
669 Like talloc_find_parent_byname() but takes a type, making it typesafe.