Adding upstream version 2.4.0.upstream/2.4.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 768 insertions, 0 deletions

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+Using talloc in Samba4
+======================
+
+.. contents::
+
+Andrew Tridgell
+August 2009
+
+The most current version of this document is available at
+   http://samba.org/ftp/unpacked/talloc/talloc_guide.txt
+
+If you are used to the "old" talloc from Samba3 before 3.0.20 then please read
+this carefully, as talloc has changed a lot. With 3.0.20 (or 3.0.14?) the
+Samba4 talloc has been ported back to Samba3, so this guide applies to both.
+
+The new talloc is a hierarchical, reference counted memory pool system
+with destructors. Quite a mouthful really, but not too bad once you
+get used to it.
+
+Perhaps the biggest change from Samba3 is that there is no distinction
+between a "talloc context" and a "talloc pointer". Any pointer
+returned from talloc() is itself a valid talloc context. This means
+you can do this::
+
+  struct foo *X = talloc(mem_ctx, struct foo);
+  X->name = talloc_strdup(X, "foo");
+
+and the pointer X->name would be a "child" of the talloc context "X"
+which is itself a child of "mem_ctx". So if you do talloc_free(mem_ctx)
+then it is all destroyed, whereas if you do talloc_free(X) then just X
+and X->name are destroyed, and if you do talloc_free(X->name) then
+just the name element of X is destroyed.
+
+If you think about this, then what this effectively gives you is an
+n-ary tree, where you can free any part of the tree with
+talloc_free().
+
+If you find this confusing, then I suggest you run the testsuite to
+watch talloc in action. You may also like to add your own tests to
+testsuite.c to clarify how some particular situation is handled.
+
+
+Performance
+-----------
+
+All the additional features of talloc() over malloc() do come at a
+price. We have a simple performance test in Samba4 that measures
+talloc() versus malloc() performance, and it seems that talloc() is
+about 4% slower than malloc() on my x86 Debian Linux box. For Samba,
+the great reduction in code complexity that we get by using talloc
+makes this worthwhile, especially as the total overhead of
+talloc/malloc in Samba is already quite small.
+
+
+talloc API
+----------
+
+The following is a complete guide to the talloc API. Read it all at
+least twice.
+
+Multi-threading
+---------------
+
+talloc itself does not deal with threads. It is thread-safe (assuming  
+the underlying "malloc" is), as long as each thread uses different  
+memory contexts.
+If two threads use the same context then they need to synchronize in
+order to be safe. In particular:
+- when using talloc_enable_leak_report(), giving directly NULL as a  
+parent context implicitly refers to a hidden "null context" global  
+variable, so this should not be used in a multi-threaded environment  
+without proper synchronization. In threaded code turn off null tracking using
+talloc_disable_null_tracking(). ;
+- the context returned by talloc_autofree_context() is also global so  
+shouldn't be used by several threads simultaneously without  
+synchronization.
+
+talloc and shared objects
+-------------------------
+
+talloc can be used in shared objects. Special care needs to be taken
+to never use talloc_autofree_context() in code that might be loaded
+with dlopen() and unloaded with dlclose(), as talloc_autofree_context()
+internally uses atexit(3). Some platforms like modern Linux handles
+this fine, but for example FreeBSD does not deal well with dlopen()
+and atexit() used simultaneously: dlclose() does not clean up the list
+of atexit-handlers, so when the program exits the code that was
+registered from within talloc_autofree_context() is gone, the program
+crashes at exit.
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+(type *)talloc(const void *context, type);
+
+The talloc() macro is the core of the talloc library. It takes a
+memory context and a type, and returns a pointer to a new area of
+memory of the given type.
+
+The returned pointer is itself a talloc context, so you can use it as
+the context argument to more calls to talloc if you wish.
+
+The returned pointer is a "child" of the supplied context. This means
+that if you talloc_free() the context then the new child disappears as
+well. Alternatively you can free just the child.
+
+The context argument to talloc() can be NULL, in which case a new top
+level context is created. 
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_size(const void *context, size_t size);
+
+The function talloc_size() should be used when you don't have a
+convenient type to pass to talloc(). Unlike talloc(), it is not type
+safe (as it returns a void *), so you are on your own for type checking.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+(typeof(ptr)) talloc_ptrtype(const void *ctx, ptr);
+
+The talloc_ptrtype() macro should be used when you have a pointer and
+want to allocate memory to point at with this pointer. When compiling
+with gcc >= 3 it is typesafe. Note this is a wrapper of talloc_size()
+and talloc_get_name() will return the current location in the source file.
+and not the type.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+int talloc_free(void *ptr);
+
+The talloc_free() function frees a piece of talloc memory, and all its
+children. You can call talloc_free() on any pointer returned by
+talloc().
+
+The return value of talloc_free() indicates success or failure, with 0
+returned for success and -1 for failure. A possible failure condition
+is if the pointer had a destructor attached to it and the destructor
+returned -1. See talloc_set_destructor() for details on
+destructors. Likewise, if "ptr" is NULL, then the function will make
+no modifications and returns -1.
+
+From version 2.0 and onwards, as a special case, talloc_free() is
+refused on pointers that have more than one parent associated, as talloc
+would have no way of knowing which parent should be removed. This is
+different from older versions in the sense that always the reference to
+the most recently established parent has been destroyed. Hence to free a
+pointer that has more than one parent please use talloc_unlink().
+
+To help you find problems in your code caused by this behaviour, if
+you do try and free a pointer with more than one parent then the
+talloc logging function will be called to give output like this:
+
+  ERROR: talloc_free with references at some_dir/source/foo.c:123
+  	reference at some_dir/source/other.c:325
+  	reference at some_dir/source/third.c:121
+
+Please see the documentation for talloc_set_log_fn() and
+talloc_set_log_stderr() for more information on talloc logging
+functions.
+
+talloc_free() operates recursively on its children.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void talloc_free_children(void *ptr);
+
+The talloc_free_children() walks along the list of all children of a
+talloc context and talloc_free()s only the children, not the context
+itself.
+
+A NULL argument is handled as no-op.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_reference(const void *context, const void *ptr);
+
+The talloc_reference() function makes "context" an additional parent
+of "ptr".
+
+The return value of talloc_reference() is always the original pointer
+"ptr", unless talloc ran out of memory in creating the reference in
+which case it will return NULL (each additional reference consumes
+around 48 bytes of memory on intel x86 platforms).
+
+If "ptr" is NULL, then the function is a no-op, and simply returns NULL.
+
+After creating a reference you can free it in one of the following
+ways:
+
+  - you can talloc_free() any parent of the original pointer. That
+    will reduce the number of parents of this pointer by 1, and will
+    cause this pointer to be freed if it runs out of parents.
+
+  - you can talloc_free() the pointer itself if it has at maximum one
+    parent. This behaviour has been changed since the release of version
+    2.0. Further information in the description of "talloc_free".
+
+For more control on which parent to remove, see talloc_unlink()
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+int talloc_unlink(const void *context, void *ptr);
+
+The talloc_unlink() function removes a specific parent from ptr. The
+context passed must either be a context used in talloc_reference()
+with this pointer, or must be a direct parent of ptr. 
+
+Note that if the parent has already been removed using talloc_free()
+then this function will fail and will return -1.  Likewise, if "ptr"
+is NULL, then the function will make no modifications and return -1.
+
+You can just use talloc_free() instead of talloc_unlink() if there
+is at maximum one parent. This behaviour has been changed since the
+release of version 2.0. Further information in the description of
+"talloc_free".
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void talloc_set_destructor(const void *ptr, int (*destructor)(void *));
+
+The function talloc_set_destructor() sets the "destructor" for the
+pointer "ptr". A destructor is a function that is called when the
+memory used by a pointer is about to be released. The destructor
+receives the pointer as an argument, and should return 0 for success
+and -1 for failure.
+
+The destructor can do anything it wants to, including freeing other
+pieces of memory. A common use for destructors is to clean up
+operating system resources (such as open file descriptors) contained
+in the structure the destructor is placed on.
+
+You can only place one destructor on a pointer. If you need more than
+one destructor then you can create a zero-length child of the pointer
+and place an additional destructor on that.
+
+To remove a destructor call talloc_set_destructor() with NULL for the
+destructor.
+
+If your destructor attempts to talloc_free() the pointer that it is
+the destructor for then talloc_free() will return -1 and the free will
+be ignored. This would be a pointless operation anyway, as the
+destructor is only called when the memory is just about to go away.
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+int talloc_increase_ref_count(const void *ptr);
+
+The talloc_increase_ref_count(ptr) function is exactly equivalent to:
+
+  talloc_reference(NULL, ptr);
+
+You can use either syntax, depending on which you think is clearer in
+your code.
+
+It returns 0 on success and -1 on failure.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+size_t talloc_reference_count(const void *ptr);
+
+Return the number of references to the pointer.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void talloc_set_name(const void *ptr, const char *fmt, ...);
+
+Each talloc pointer has a "name". The name is used principally for
+debugging purposes, although it is also possible to set and get the
+name on a pointer in as a way of "marking" pointers in your code.
+
+The main use for names on pointer is for "talloc reports". See
+talloc_report() and talloc_report_full() for details. Also see
+talloc_enable_leak_report() and talloc_enable_leak_report_full().
+
+The talloc_set_name() function allocates memory as a child of the
+pointer. It is logically equivalent to:
+  talloc_set_name_const(ptr, talloc_asprintf(ptr, fmt, ...));
+
+Note that multiple calls to talloc_set_name() will allocate more
+memory without releasing the name. All of the memory is released when
+the ptr is freed using talloc_free().
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void talloc_set_name_const(const void *ptr, const char *name);
+
+The function talloc_set_name_const() is just like talloc_set_name(),
+but it takes a string constant, and is much faster. It is extensively
+used by the "auto naming" macros, such as talloc_p().
+
+This function does not allocate any memory. It just copies the
+supplied pointer into the internal representation of the talloc
+ptr. This means you must not pass a name pointer to memory that will
+disappear before the ptr is freed with talloc_free().
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_named(const void *context, size_t size, const char *fmt, ...);
+
+The talloc_named() function creates a named talloc pointer. It is
+equivalent to:
+
+   ptr = talloc_size(context, size);
+   talloc_set_name(ptr, fmt, ....);
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_named_const(const void *context, size_t size, const char *name);
+
+This is equivalent to::
+
+   ptr = talloc_size(context, size);
+   talloc_set_name_const(ptr, name);
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+const char *talloc_get_name(const void *ptr);
+
+This returns the current name for the given talloc pointer. See
+talloc_set_name() for details.
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_init(const char *fmt, ...);
+
+This function creates a zero length named talloc context as a top
+level context. It is equivalent to::
+
+  talloc_named(NULL, 0, fmt, ...);
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_new(void *ctx);
+
+This is a utility macro that creates a new memory context hanging
+off an exiting context, automatically naming it "talloc_new: __location__"
+where __location__ is the source line it is called from. It is
+particularly useful for creating a new temporary working context.
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+(type *)talloc_realloc(const void *context, void *ptr, type, count);
+
+The talloc_realloc() macro changes the size of a talloc
+pointer. The "count" argument is the number of elements of type "type"
+that you want the resulting pointer to hold. 
+
+talloc_realloc() has the following equivalences::
+
+  talloc_realloc(context, NULL, type, 1) ==> talloc(context, type);
+  talloc_realloc(context, NULL, type, N) ==> talloc_array(context, type, N);
+  talloc_realloc(context, ptr, type, 0)  ==> talloc_free(ptr);
+
+The "context" argument is only used if "ptr" is NULL, otherwise it is
+ignored.
+
+talloc_realloc() returns the new pointer, or NULL on failure. The call
+will fail either due to a lack of memory, or because the pointer has
+more than one parent (see talloc_reference()).
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_realloc_size(const void *context, void *ptr, size_t size);
+
+the talloc_realloc_size() function is useful when the type is not 
+known so the typesafe talloc_realloc() cannot be used.
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_steal(const void *new_ctx, const void *ptr);
+
+The talloc_steal() function changes the parent context of a talloc
+pointer. It is typically used when the context that the pointer is
+currently a child of is going to be freed and you wish to keep the
+memory for a longer time. 
+
+The talloc_steal() function returns the pointer that you pass it. It
+does not have any failure modes.
+
+NOTE: It is possible to produce loops in the parent/child relationship
+if you are not careful with talloc_steal(). No guarantees are provided
+as to your sanity or the safety of your data if you do this.
+
+talloc_steal (new_ctx, NULL) will return NULL with no sideeffects.
+
+Note that if you try and call talloc_steal() on a pointer that has
+more than one parent then the result is ambiguous. Talloc will choose
+to remove the parent that is currently indicated by talloc_parent()
+and replace it with the chosen parent. You will also get a message
+like this via the talloc logging functions:
+
+  WARNING: talloc_steal with references at some_dir/source/foo.c:123
+  	reference at some_dir/source/other.c:325
+  	reference at some_dir/source/third.c:121
+
+To unambiguously change the parent of a pointer please see the
+function talloc_reparent(). See the talloc_set_log_fn() documentation
+for more information on talloc logging.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_reparent(const void *old_parent, const void *new_parent, const void *ptr);
+
+The talloc_reparent() function changes the parent context of a talloc
+pointer. It is typically used when the context that the pointer is
+currently a child of is going to be freed and you wish to keep the
+memory for a longer time.
+
+The talloc_reparent() function returns the pointer that you pass it. It
+does not have any failure modes.
+
+The difference between talloc_reparent() and talloc_steal() is that
+talloc_reparent() can specify which parent you wish to change. This is
+useful when a pointer has multiple parents via references.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_parent(const void *ptr);
+
+The talloc_parent() function returns the current talloc parent. This
+is usually the pointer under which this memory was originally created,
+but it may have changed due to a talloc_steal() or talloc_reparent()
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+size_t talloc_total_size(const void *ptr);
+
+The talloc_total_size() function returns the total size in bytes used
+by this pointer and all child pointers. Mostly useful for debugging.
+
+Passing NULL is allowed, but it will only give a meaningful result if
+talloc_enable_leak_report() or talloc_enable_leak_report_full() has
+been called.
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+size_t talloc_total_blocks(const void *ptr);
+
+The talloc_total_blocks() function returns the total memory block
+count used by this pointer and all child pointers. Mostly useful for
+debugging.
+
+Passing NULL is allowed, but it will only give a meaningful result if
+talloc_enable_leak_report() or talloc_enable_leak_report_full() has
+been called.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void talloc_report_depth_cb(const void *ptr, int depth, int max_depth,
+			    void (*callback)(const void *ptr,
+			    		     int depth, int max_depth,
+					     int is_ref,
+					     void *priv),
+			    void *priv);
+
+This provides a more flexible reports than talloc_report(). It
+will recursively call the callback for the entire tree of memory
+referenced by the pointer. References in the tree are passed with
+is_ref = 1 and the pointer that is referenced.
+
+You can pass NULL for the pointer, in which case a report is
+printed for the top level memory context, but only if
+talloc_enable_leak_report() or talloc_enable_leak_report_full()
+has been called.
+
+The recursion is stopped when depth >= max_depth.
+max_depth = -1 means only stop at leaf nodes.
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void talloc_report_depth_file(const void *ptr, int depth, int max_depth, FILE *f);
+
+This provides a more flexible reports than talloc_report(). It
+will let you specify the depth and max_depth.
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void talloc_report(const void *ptr, FILE *f);
+
+The talloc_report() function prints a summary report of all memory
+used by ptr. One line of report is printed for each immediate child of
+ptr, showing the total memory and number of blocks used by that child.
+
+You can pass NULL for the pointer, in which case a report is printed
+for the top level memory context, but only if
+talloc_enable_leak_report() or talloc_enable_leak_report_full() has
+been called.
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void talloc_report_full(const void *ptr, FILE *f);
+
+This provides a more detailed report than talloc_report(). It will
+recursively print the entire tree of memory referenced by the
+pointer. References in the tree are shown by giving the name of the
+pointer that is referenced.
+
+You can pass NULL for the pointer, in which case a report is printed
+for the top level memory context, but only if
+talloc_enable_leak_report() or talloc_enable_leak_report_full() has
+been called.
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void talloc_enable_leak_report(void);
+
+This enables calling of talloc_report(NULL, stderr) when the program
+exits. In Samba4 this is enabled by using the --leak-report command
+line option.
+
+For it to be useful, this function must be called before any other
+talloc function as it establishes a "null context" that acts as the
+top of the tree. If you don't call this function first then passing
+NULL to talloc_report() or talloc_report_full() won't give you the
+full tree printout.
+
+Here is a typical talloc report:
+
+talloc report on 'null_context' (total 267 bytes in 15 blocks)
+        libcli/auth/spnego_parse.c:55  contains     31 bytes in   2 blocks
+        libcli/auth/spnego_parse.c:55  contains     31 bytes in   2 blocks
+        iconv(UTF8,CP850)              contains     42 bytes in   2 blocks
+        libcli/auth/spnego_parse.c:55  contains     31 bytes in   2 blocks
+        iconv(CP850,UTF8)              contains     42 bytes in   2 blocks
+        iconv(UTF8,UTF-16LE)           contains     45 bytes in   2 blocks
+        iconv(UTF-16LE,UTF8)           contains     45 bytes in   2 blocks
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void talloc_enable_leak_report_full(void);
+
+This enables calling of talloc_report_full(NULL, stderr) when the
+program exits. In Samba4 this is enabled by using the
+--leak-report-full command line option.
+
+For it to be useful, this function must be called before any other
+talloc function as it establishes a "null context" that acts as the
+top of the tree. If you don't call this function first then passing
+NULL to talloc_report() or talloc_report_full() won't give you the
+full tree printout.
+
+Here is a typical full report:
+
+full talloc report on 'root' (total 18 bytes in 8 blocks)
+    p1                             contains     18 bytes in   7 blocks (ref 0)
+        r1                             contains     13 bytes in   2 blocks (ref 0)
+            reference to: p2
+        p2                             contains      1 bytes in   1 blocks (ref 1)
+        x3                             contains      1 bytes in   1 blocks (ref 0)
+        x2                             contains      1 bytes in   1 blocks (ref 0)
+        x1                             contains      1 bytes in   1 blocks (ref 0)
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void talloc_enable_null_tracking(void);
+
+This enables tracking of the NULL memory context without enabling leak
+reporting on exit. Useful for when you want to do your own leak
+reporting call via talloc_report_null_full();
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void talloc_disable_null_tracking(void);
+
+This disables tracking of the NULL memory context.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+(type *)talloc_zero(const void *ctx, type);
+
+The talloc_zero() macro is equivalent to::
+
+  ptr = talloc(ctx, type);
+  if (ptr) memset(ptr, 0, sizeof(type));
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_zero_size(const void *ctx, size_t size)
+
+The talloc_zero_size() function is useful when you don't have a known type
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_memdup(const void *ctx, const void *p, size_t size);
+
+The talloc_memdup() function is equivalent to::
+
+  ptr = talloc_size(ctx, size);
+  if (ptr) memcpy(ptr, p, size);
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+char *talloc_strdup(const void *ctx, const char *p);
+
+The talloc_strdup() function is equivalent to::
+
+  ptr = talloc_size(ctx, strlen(p)+1);
+  if (ptr) memcpy(ptr, p, strlen(p)+1);
+
+This functions sets the name of the new pointer to the passed
+string. This is equivalent to::
+
+   talloc_set_name_const(ptr, ptr)
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+char *talloc_strndup(const void *t, const char *p, size_t n);
+
+The talloc_strndup() function is the talloc equivalent of the C
+library function strndup()
+
+This functions sets the name of the new pointer to the passed
+string. This is equivalent to:
+   talloc_set_name_const(ptr, ptr)
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+char *talloc_append_string(const void *t, char *orig, const char *append);
+
+The talloc_append_string() function appends the given formatted
+string to the given string.
+
+This function sets the name of the new pointer to the new
+string. This is equivalent to::
+
+   talloc_set_name_const(ptr, ptr)
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+char *talloc_vasprintf(const void *t, const char *fmt, va_list ap);
+
+The talloc_vasprintf() function is the talloc equivalent of the C
+library function vasprintf()
+
+This functions sets the name of the new pointer to the new
+string. This is equivalent to::
+
+   talloc_set_name_const(ptr, ptr)
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+char *talloc_asprintf(const void *t, const char *fmt, ...);
+
+The talloc_asprintf() function is the talloc equivalent of the C
+library function asprintf()
+
+This functions sets the name of the new pointer to the new
+string. This is equivalent to::
+
+   talloc_set_name_const(ptr, ptr)
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+char *talloc_asprintf_append(char *s, const char *fmt, ...);
+
+The talloc_asprintf_append() function appends the given formatted
+string to the given string.
+Use this variant when the string in the current talloc buffer may
+have been truncated in length.
+
+This functions sets the name of the new pointer to the new
+string. This is equivalent to::
+
+   talloc_set_name_const(ptr, ptr)
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+char *talloc_asprintf_append_buffer(char *s, const char *fmt, ...);
+
+The talloc_asprintf_append() function appends the given formatted 
+string to the end of the currently allocated talloc buffer.
+Use this variant when the string in the current talloc buffer has
+not been changed.
+
+This functions sets the name of the new pointer to the new
+string. This is equivalent to::
+
+   talloc_set_name_const(ptr, ptr)
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+((type *)talloc_array(const void *ctx, type, unsigned int count);
+
+The talloc_array() macro is equivalent to::
+
+  (type *)talloc_size(ctx, sizeof(type) * count);
+
+except that it provides integer overflow protection for the multiply,
+returning NULL if the multiply overflows.
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_array_size(const void *ctx, size_t size, unsigned int count);
+
+The talloc_array_size() function is useful when the type is not
+known. It operates in the same way as talloc_array(), but takes a size
+instead of a type.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+(typeof(ptr)) talloc_array_ptrtype(const void *ctx, ptr, unsigned int count);
+
+The talloc_ptrtype() macro should be used when you have a pointer to an array
+and want to allocate memory of an array to point at with this pointer. When compiling
+with gcc >= 3 it is typesafe. Note this is a wrapper of talloc_array_size()
+and talloc_get_name() will return the current location in the source file.
+and not the type.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_realloc_fn(const void *ctx, void *ptr, size_t size);
+
+This is a non-macro version of talloc_realloc(), which is useful 
+as libraries sometimes want a ralloc function pointer. A realloc()
+implementation encapsulates the functionality of malloc(), free() and
+realloc() in one call, which is why it is useful to be able to pass
+around a single function pointer.
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_autofree_context(void);
+
+This is a handy utility function that returns a talloc context
+which will be automatically freed on program exit. This can be used
+to reduce the noise in memory leak reports.
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_check_name(const void *ptr, const char *name);
+
+This function checks if a pointer has the specified name. If it does
+then the pointer is returned. It it doesn't then NULL is returned.
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+(type *)talloc_get_type(const void *ptr, type);
+
+This macro allows you to do type checking on talloc pointers. It is
+particularly useful for void* private pointers. It is equivalent to
+this::
+
+   (type *)talloc_check_name(ptr, #type)
+
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+talloc_set_type(const void *ptr, type);
+
+This macro allows you to force the name of a pointer to be of a
+particular type. This can be used in conjunction with
+talloc_get_type() to do type checking on void* pointers.
+
+It is equivalent to this::
+
+   talloc_set_name_const(ptr, #type)
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+talloc_get_size(const void *ctx);
+
+This function lets you know the amount of memory allocated so far by
+this context. It does NOT account for subcontext memory.
+This can be used to calculate the size of an array.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void *talloc_find_parent_byname(const void *ctx, const char *name);
+
+Find a parent memory context of the current context that has the given
+name. This can be very useful in complex programs where it may be
+difficult to pass all information down to the level you need, but you
+know the structure you want is a parent of another context.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+(type *)talloc_find_parent_bytype(ctx, type);
+
+Like talloc_find_parent_byname() but takes a type, making it typesafe.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void talloc_set_log_fn(void (*log_fn)(const char *message));
+
+This function sets a logging function that talloc will use for
+warnings and errors. By default talloc will not print any warnings or
+errors.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+void talloc_set_log_stderr(void)
+
+This sets the talloc log function to write log messages to stderr.