1 <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>talloc</title><meta name="generator" content="DocBook XSL Stylesheets V1.72.0"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" lang="en"><a name="id2486772"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>talloc — hierarchical reference counted memory pool system with destructors</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">#include <talloc/talloc.h></pre></div><div class="refsect1" lang="en"><a name="id2525397"></a><h2>DESCRIPTION</h2><p>
2 If you are used to talloc from Samba3 then please read this
3 carefully, as talloc has changed a lot.
5 The new talloc is a hierarchical, reference counted memory pool
6 system with destructors. Quite a mouthful really, but not too bad
7 once you get used to it.
9 Perhaps the biggest change from Samba3 is that there is no
10 distinction between a "talloc context" and a "talloc pointer". Any
11 pointer returned from talloc() is itself a valid talloc context.
12 This means you can do this:
13 </p><pre class="programlisting">
14 struct foo *X = talloc(mem_ctx, struct foo);
15 X->name = talloc_strdup(X, "foo");
17 and the pointer <code class="literal">X->name</code>
18 would be a "child" of the talloc context <code class="literal">X</code> which is itself a child of
19 <code class="literal">mem_ctx</code>. So if you do
20 <code class="literal">talloc_free(mem_ctx)</code> then
21 it is all destroyed, whereas if you do <code class="literal">talloc_free(X)</code> then just <code class="literal">X</code> and <code class="literal">X->name</code> are destroyed, and if
22 you do <code class="literal">talloc_free(X->name)</code> then just
23 the name element of <code class="literal">X</code> is
26 If you think about this, then what this effectively gives you is an
27 n-ary tree, where you can free any part of the tree with
30 If you find this confusing, then I suggest you run the <code class="literal">testsuite</code> program to watch talloc
31 in action. You may also like to add your own tests to <code class="literal">testsuite.c</code> to clarify how some
32 particular situation is handled.
33 </p></div><div class="refsect1" lang="en"><a name="id2486869"></a><h2>TALLOC API</h2><p>
34 The following is a complete guide to the talloc API. Read it all at
36 </p><div class="refsect2" lang="en"><a name="id2486878"></a><h3>(type *)talloc(const void *ctx, type);</h3><p>
37 The talloc() macro is the core of the talloc library. It takes a
38 memory <span class="italic">ctx</span> and a <span class="italic">type</span>, and returns a pointer to a new
39 area of memory of the given <span class="italic">type</span>.
41 The returned pointer is itself a talloc context, so you can use
42 it as the <span class="italic">ctx</span> argument to more
43 calls to talloc() if you wish.
45 The returned pointer is a "child" of the supplied context. This
46 means that if you talloc_free() the <span class="italic">ctx</span> then the new child disappears as
47 well. Alternatively you can free just the child.
49 The <span class="italic">ctx</span> argument to talloc()
50 can be NULL, in which case a new top level context is created.
51 </p></div><div class="refsect2" lang="en"><a name="id2486942"></a><h3>void *talloc_size(const void *ctx, size_t size);</h3><p>
52 The function talloc_size() should be used when you don't have a
53 convenient type to pass to talloc(). Unlike talloc(), it is not
54 type safe (as it returns a void *), so you are on your own for
56 </p></div><div class="refsect2" lang="en"><a name="id2486956"></a><h3>(typeof(ptr)) talloc_ptrtype(const void *ctx, ptr);</h3><p>
57 The talloc_ptrtype() macro should be used when you have a pointer and
58 want to allocate memory to point at with this pointer. When compiling
59 with gcc >= 3 it is typesafe. Note this is a wrapper of talloc_size()
60 and talloc_get_name() will return the current location in the source file.
62 </p></div><div class="refsect2" lang="en"><a name="id2486971"></a><h3>int talloc_free(void *ptr);</h3><p>
63 The talloc_free() function frees a piece of talloc memory, and
64 all its children. You can call talloc_free() on any pointer
67 The return value of talloc_free() indicates success or failure,
68 with 0 returned for success and -1 for failure. The only
69 possible failure condition is if <span class="italic">ptr</span> had a destructor attached to it and
70 the destructor returned -1. See <a href="#talloc_set_destructor" title="void talloc_set_destructor(const void *ptr, int (*destructor)(void *));">“<span class="quote">talloc_set_destructor()</span>”</a>
71 for details on destructors.
73 If this pointer has an additional parent when talloc_free() is
74 called then the memory is not actually released, but instead the
75 most recently established parent is destroyed. See <a href="#talloc_reference" title="void *talloc_reference(const void *ctx, const void *ptr);">“<span class="quote">talloc_reference()</span>”</a>
76 for details on establishing additional parents.
78 For more control on which parent is removed, see <a href="#talloc_unlink" title="int talloc_unlink(const void *ctx, const void *ptr);">“<span class="quote">talloc_unlink()</span>”</a>.
80 talloc_free() operates recursively on its children.
81 </p></div><div class="refsect2" lang="en"><a name="talloc_reference"></a><h3>void *talloc_reference(const void *ctx, const void *ptr);</h3><p>
82 The talloc_reference() function makes <span class="italic">ctx</span> an additional parent of <span class="italic">ptr</span>.
84 The return value of talloc_reference() is always the original
85 pointer <span class="italic">ptr</span>, unless talloc ran
86 out of memory in creating the reference in which case it will
87 return NULL (each additional reference consumes around 48 bytes
88 of memory on intel x86 platforms).
90 If <span class="italic">ptr</span> is NULL, then the
91 function is a no-op, and simply returns NULL.
93 After creating a reference you can free it in one of the
96 </p><div class="itemizedlist"><ul type="disc"><li><p>
97 you can talloc_free() any parent of the original pointer.
98 That will reduce the number of parents of this pointer by 1,
99 and will cause this pointer to be freed if it runs out of
102 you can talloc_free() the pointer itself. That will destroy
103 the most recently established parent to the pointer and leave
104 the pointer as a child of its current parent.
105 </p></li></ul></div><p>
107 For more control on which parent to remove, see <a href="#talloc_unlink" title="int talloc_unlink(const void *ctx, const void *ptr);">“<span class="quote">talloc_unlink()</span>”</a>.
108 </p></div><div class="refsect2" lang="en"><a name="talloc_unlink"></a><h3>int talloc_unlink(const void *ctx, const void *ptr);</h3><p>
109 The talloc_unlink() function removes a specific parent from
110 <span class="italic">ptr</span>. The <span class="italic">ctx</span> passed must either be a context used
111 in talloc_reference() with this pointer, or must be a direct
114 Note that if the parent has already been removed using
115 talloc_free() then this function will fail and will return -1.
116 Likewise, if <span class="italic">ptr</span> is NULL, then
117 the function will make no modifications and return -1.
119 Usually you can just use talloc_free() instead of
120 talloc_unlink(), but sometimes it is useful to have the
121 additional control on which parent is removed.
122 </p></div><div class="refsect2" lang="en"><a name="talloc_set_destructor"></a><h3>void talloc_set_destructor(const void *ptr, int (*destructor)(void *));</h3><p>
123 The function talloc_set_destructor() sets the <span class="italic">destructor</span> for the pointer <span class="italic">ptr</span>. A <span class="italic">destructor</span> is a function that is called
124 when the memory used by a pointer is about to be released. The
125 destructor receives <span class="italic">ptr</span> as an
126 argument, and should return 0 for success and -1 for failure.
128 The <span class="italic">destructor</span> can do anything
129 it wants to, including freeing other pieces of memory. A common
130 use for destructors is to clean up operating system resources
131 (such as open file descriptors) contained in the structure the
132 destructor is placed on.
134 You can only place one destructor on a pointer. If you need more
135 than one destructor then you can create a zero-length child of
136 the pointer and place an additional destructor on that.
138 To remove a destructor call talloc_set_destructor() with NULL for
141 If your destructor attempts to talloc_free() the pointer that it
142 is the destructor for then talloc_free() will return -1 and the
143 free will be ignored. This would be a pointless operation
144 anyway, as the destructor is only called when the memory is just
146 </p></div><div class="refsect2" lang="en"><a name="id2488786"></a><h3>int talloc_increase_ref_count(const void *<span class="italic">ptr</span>);</h3><p>
147 The talloc_increase_ref_count(<span class="italic">ptr</span>) function is exactly equivalent to:
148 </p><pre class="programlisting">talloc_reference(NULL, ptr);</pre><p>
149 You can use either syntax, depending on which you think is
150 clearer in your code.
152 It returns 0 on success and -1 on failure.
153 </p></div><div class="refsect2" lang="en"><a name="id2488823"></a><h3>size_t talloc_reference_count(const void *<span class="italic">ptr</span>);</h3><p>
154 Return the number of references to the pointer.
155 </p></div><div class="refsect2" lang="en"><a name="talloc_set_name"></a><h3>void talloc_set_name(const void *ptr, const char *fmt, ...);</h3><p>
156 Each talloc pointer has a "name". The name is used principally
157 for debugging purposes, although it is also possible to set and
158 get the name on a pointer in as a way of "marking" pointers in
161 The main use for names on pointer is for "talloc reports". See
162 <a href="#talloc_report" title="void talloc_report(const void *ptr, FILE *f);">“<span class="quote">talloc_report_depth_cb()</span>”</a>,
163 <a href="#talloc_report" title="void talloc_report(const void *ptr, FILE *f);">“<span class="quote">talloc_report_depth_file()</span>”</a>,
164 <a href="#talloc_report" title="void talloc_report(const void *ptr, FILE *f);">“<span class="quote">talloc_report()</span>”</a>
165 <a href="#talloc_report" title="void talloc_report(const void *ptr, FILE *f);">“<span class="quote">talloc_report()</span>”</a>
166 and <a href="#talloc_report_full" title="void talloc_report_full(const void *ptr, FILE *f);">“<span class="quote">talloc_report_full()</span>”</a>
167 for details. Also see <a href="#talloc_enable_leak_report" title="void talloc_enable_leak_report(void);">“<span class="quote">talloc_enable_leak_report()</span>”</a>
168 and <a href="#talloc_enable_leak_report_full" title="void talloc_enable_leak_report_full(void);">“<span class="quote">talloc_enable_leak_report_full()</span>”</a>.
170 The talloc_set_name() function allocates memory as a child of the
171 pointer. It is logically equivalent to:
172 </p><pre class="programlisting">talloc_set_name_const(ptr, talloc_asprintf(ptr, fmt, ...));</pre><p>
173 Note that multiple calls to talloc_set_name() will allocate more
174 memory without releasing the name. All of the memory is released
175 when the ptr is freed using talloc_free().
176 </p></div><div class="refsect2" lang="en"><a name="id2488942"></a><h3>void talloc_set_name_const(const void *<span class="italic">ptr</span>, const char *<span class="italic">name</span>);</h3><p>
177 The function talloc_set_name_const() is just like
178 talloc_set_name(), but it takes a string constant, and is much
179 faster. It is extensively used by the "auto naming" macros, such
182 This function does not allocate any memory. It just copies the
183 supplied pointer into the internal representation of the talloc
184 ptr. This means you must not pass a <span class="italic">name</span> pointer to memory that will
185 disappear before <span class="italic">ptr</span> is freed
187 </p></div><div class="refsect2" lang="en"><a name="id2488986"></a><h3>void *talloc_named(const void *<span class="italic">ctx</span>, size_t <span class="italic">size</span>, const char *<span class="italic">fmt</span>, ...);</h3><p>
188 The talloc_named() function creates a named talloc pointer. It
190 </p><pre class="programlisting">ptr = talloc_size(ctx, size);
191 talloc_set_name(ptr, fmt, ....);</pre></div><div class="refsect2" lang="en"><a name="id2489022"></a><h3>void *talloc_named_const(const void *<span class="italic">ctx</span>, size_t <span class="italic">size</span>, const char *<span class="italic">name</span>);</h3><p>
192 This is equivalent to:
193 </p><pre class="programlisting">ptr = talloc_size(ctx, size);
194 talloc_set_name_const(ptr, name);</pre></div><div class="refsect2" lang="en"><a name="id2489056"></a><h3>const char *talloc_get_name(const void *<span class="italic">ptr</span>);</h3><p>
195 This returns the current name for the given talloc pointer,
196 <span class="italic">ptr</span>. See <a href="#talloc_set_name" title="void talloc_set_name(const void *ptr, const char *fmt, ...);">“<span class="quote">talloc_set_name()</span>”</a>
198 </p></div><div class="refsect2" lang="en"><a name="id2489087"></a><h3>void *talloc_init(const char *<span class="italic">fmt</span>, ...);</h3><p>
199 This function creates a zero length named talloc context as a top
200 level context. It is equivalent to:
201 </p><pre class="programlisting">talloc_named(NULL, 0, fmt, ...);</pre></div><div class="refsect2" lang="en"><a name="id2489110"></a><h3>void *talloc_new(void *<span class="italic">ctx</span>);</h3><p>
202 This is a utility macro that creates a new memory context hanging
203 off an exiting context, automatically naming it "talloc_new:
204 __location__" where __location__ is the source line it is called
205 from. It is particularly useful for creating a new temporary
207 </p></div><div class="refsect2" lang="en"><a name="id2489130"></a><h3>(<span class="italic">type</span> *)talloc_realloc(const void *<span class="italic">ctx</span>, void *<span class="italic">ptr</span>, <span class="italic">type</span>, <span class="italic">count</span>);</h3><p>
208 The talloc_realloc() macro changes the size of a talloc pointer.
209 It has the following equivalences:
210 </p><pre class="programlisting">talloc_realloc(ctx, NULL, type, 1) ==> talloc(ctx, type);
211 talloc_realloc(ctx, ptr, type, 0) ==> talloc_free(ptr);</pre><p>
212 The <span class="italic">ctx</span> argument is only used
213 if <span class="italic">ptr</span> is not NULL, otherwise
216 talloc_realloc() returns the new pointer, or NULL on failure.
217 The call will fail either due to a lack of memory, or because the
218 pointer has more than one parent (see <a href="#talloc_reference" title="void *talloc_reference(const void *ctx, const void *ptr);">“<span class="quote">talloc_reference()</span>”</a>).
219 </p></div><div class="refsect2" lang="en"><a name="id2534877"></a><h3>void *talloc_realloc_size(const void *ctx, void *ptr, size_t size);</h3><p>
220 the talloc_realloc_size() function is useful when the type is not
221 known so the type-safe talloc_realloc() cannot be used.
222 </p></div><div class="refsect2" lang="en"><a name="id2534889"></a><h3>TYPE *talloc_steal(const void *<span class="italic">new_ctx</span>, const TYPE *<span class="italic">ptr</span>);</h3><p>
223 The talloc_steal() function changes the parent context of a
224 talloc pointer. It is typically used when the context that the
225 pointer is currently a child of is going to be freed and you wish
226 to keep the memory for a longer time.
228 The talloc_steal() function returns the pointer that you pass it.
229 It does not have any failure modes.
231 NOTE: It is possible to produce loops in the parent/child
232 relationship if you are not careful with talloc_steal(). No
233 guarantees are provided as to your sanity or the safety of your
235 </p></div><div class="refsect2" lang="en"><a name="id2534927"></a><h3>TYPE *talloc_move(const void *<span class="italic">new_ctx</span>, TYPE **<span class="italic">ptr</span>);</h3><p>
236 The talloc_move() function is a wrapper around
237 talloc_steal() which zeros the source pointer after the
238 move. This avoids a potential source of bugs where a
239 programmer leaves a pointer in two structures, and uses the
240 pointer from the old structure after it has been moved to a
242 </p></div><div class="refsect2" lang="en"><a name="id2534953"></a><h3>size_t talloc_total_size(const void *<span class="italic">ptr</span>);</h3><p>
243 The talloc_total_size() function returns the total size in bytes
244 used by this pointer and all child pointers. Mostly useful for
247 Passing NULL is allowed, but it will only give a meaningful
248 result if talloc_enable_leak_report() or
249 talloc_enable_leak_report_full() has been called.
250 </p></div><div class="refsect2" lang="en"><a name="id2534976"></a><h3>size_t talloc_total_blocks(const void *<span class="italic">ptr</span>);</h3><p>
251 The talloc_total_blocks() function returns the total memory block
252 count used by this pointer and all child pointers. Mostly useful
255 Passing NULL is allowed, but it will only give a meaningful
256 result if talloc_enable_leak_report() or
257 talloc_enable_leak_report_full() has been called.
258 </p></div><div class="refsect2" lang="en"><a name="talloc_report"></a><h3>void talloc_report(const void *ptr, FILE *f);</h3><p>
259 The talloc_report() function prints a summary report of all
260 memory used by <span class="italic">ptr</span>. One line
261 of report is printed for each immediate child of ptr, showing the
262 total memory and number of blocks used by that child.
264 You can pass NULL for the pointer, in which case a report is
265 printed for the top level memory context, but only if
266 talloc_enable_leak_report() or talloc_enable_leak_report_full()
268 </p></div><div class="refsect2" lang="en"><a name="talloc_report_full"></a><h3>void talloc_report_full(const void *<span class="italic">ptr</span>, FILE *<span class="italic">f</span>);</h3><p>
269 This provides a more detailed report than talloc_report(). It
270 will recursively print the entire tree of memory referenced by
271 the pointer. References in the tree are shown by giving the name
272 of the pointer that is referenced.
274 You can pass NULL for the pointer, in which case a report is
275 printed for the top level memory context, but only if
276 talloc_enable_leak_report() or talloc_enable_leak_report_full()
278 </p></div><div class="refsect2" lang="en"><a name="talloc_report_depth_cb"></a><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"><tr><td><code class="funcdef">void <b class="fsfunc">talloc_report_depth_cb</b>(</code></td><td><var class="pdparam">const void *ptr</var>, </td><td> </td></tr><tr><td> </td><td><var class="pdparam">int depth</var>, </td><td> </td></tr><tr><td> </td><td><var class="pdparam">int max_depth</var>, </td><td> </td></tr><tr><td> </td><td><var class="pdparam">void (*callback)(const void *ptr, int depth, int max_depth, int is_ref, void *priv)</var>, </td><td> </td></tr><tr><td> </td><td><var class="pdparam">void *priv</var><code>)</code>;</td><td> </td></tr></table><table border="0" summary="Function argument synopsis" cellspacing="0" cellpadding="0"><tr><td><code></code> </td><td><code><var class="pdparam">const void *ptr</var>;</code></td></tr><tr><td><code></code> </td><td><code><var class="pdparam">int depth</var>;</code></td></tr><tr><td><code></code> </td><td><code><var class="pdparam">int max_depth</var>;</code></td></tr><tr><td><code></code> </td><td><code><var class="pdparam">void (*callback)(const void *ptr, int depth, int max_depth, int is_ref, void *priv)</var>;</code></td></tr><tr><td><code></code> </td><td><code><var class="pdparam">void *priv</var>;</code></td></tr></table></div><p>
279 This provides a more flexible reports than talloc_report(). It
280 will recursively call the callback for the entire tree of memory
281 referenced by the pointer. References in the tree are passed with
282 <span class="italic">is_ref = 1</span> and the pointer that is referenced.
284 You can pass NULL for the pointer, in which case a report is
285 printed for the top level memory context, but only if
286 talloc_enable_leak_report() or talloc_enable_leak_report_full()
289 The recursion is stopped when depth >= max_depth.
290 max_depth = -1 means only stop at leaf nodes.
291 </p></div><div class="refsect2" lang="en"><a name="talloc_report_depth_file"></a><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em"><tr><td><code class="funcdef">void <b class="fsfunc">talloc_report_depth_file</b>(</code></td><td><var class="pdparam">const void *ptr</var>, </td><td> </td></tr><tr><td> </td><td><var class="pdparam">int depth</var>, </td><td> </td></tr><tr><td> </td><td><var class="pdparam">int max_depth</var>, </td><td> </td></tr><tr><td> </td><td><var class="pdparam">FILE *f</var><code>)</code>;</td><td> </td></tr></table><table border="0" summary="Function argument synopsis" cellspacing="0" cellpadding="0"><tr><td><code></code> </td><td><code><var class="pdparam">const void *ptr</var>;</code></td></tr><tr><td><code></code> </td><td><code><var class="pdparam">int depth</var>;</code></td></tr><tr><td><code></code> </td><td><code><var class="pdparam">int max_depth</var>;</code></td></tr><tr><td><code></code> </td><td><code><var class="pdparam">FILE *f</var>;</code></td></tr></table></div><p>
292 This provides a more flexible reports than talloc_report(). It
293 will let you specify the depth and max_depth.
294 </p></div><div class="refsect2" lang="en"><a name="talloc_enable_leak_report"></a><h3>void talloc_enable_leak_report(void);</h3><p>
295 This enables calling of talloc_report(NULL, stderr) when the
296 program exits. In Samba4 this is enabled by using the
297 --leak-report command line option.
299 For it to be useful, this function must be called before any
300 other talloc function as it establishes a "null context" that
301 acts as the top of the tree. If you don't call this function
302 first then passing NULL to talloc_report() or
303 talloc_report_full() won't give you the full tree printout.
305 Here is a typical talloc report:
306 </p><pre class="screen">talloc report on 'null_context' (total 267 bytes in 15 blocks)
307 libcli/auth/spnego_parse.c:55 contains 31 bytes in 2 blocks
308 libcli/auth/spnego_parse.c:55 contains 31 bytes in 2 blocks
309 iconv(UTF8,CP850) contains 42 bytes in 2 blocks
310 libcli/auth/spnego_parse.c:55 contains 31 bytes in 2 blocks
311 iconv(CP850,UTF8) contains 42 bytes in 2 blocks
312 iconv(UTF8,UTF-16LE) contains 45 bytes in 2 blocks
313 iconv(UTF-16LE,UTF8) contains 45 bytes in 2 blocks
314 </pre></div><div class="refsect2" lang="en"><a name="talloc_enable_leak_report_full"></a><h3>void talloc_enable_leak_report_full(void);</h3><p>
315 This enables calling of talloc_report_full(NULL, stderr) when the
316 program exits. In Samba4 this is enabled by using the
317 --leak-report-full command line option.
319 For it to be useful, this function must be called before any
320 other talloc function as it establishes a "null context" that
321 acts as the top of the tree. If you don't call this function
322 first then passing NULL to talloc_report() or
323 talloc_report_full() won't give you the full tree printout.
325 Here is a typical full report:
326 </p><pre class="screen">full talloc report on 'root' (total 18 bytes in 8 blocks)
327 p1 contains 18 bytes in 7 blocks (ref 0)
328 r1 contains 13 bytes in 2 blocks (ref 0)
330 p2 contains 1 bytes in 1 blocks (ref 1)
331 x3 contains 1 bytes in 1 blocks (ref 0)
332 x2 contains 1 bytes in 1 blocks (ref 0)
333 x1 contains 1 bytes in 1 blocks (ref 0)
334 </pre></div><div class="refsect2" lang="en"><a name="id2535284"></a><h3>(<span class="italic">type</span> *)talloc_zero(const void *<span class="italic">ctx</span>, <span class="italic">type</span>);</h3><p>
335 The talloc_zero() macro is equivalent to:
336 </p><pre class="programlisting">ptr = talloc(ctx, type);
337 if (ptr) memset(ptr, 0, sizeof(type));</pre></div><div class="refsect2" lang="en"><a name="id2535318"></a><h3>void *talloc_zero_size(const void *<span class="italic">ctx</span>, size_t <span class="italic">size</span>)</h3><p>
338 The talloc_zero_size() function is useful when you don't have a
340 </p></div><div class="refsect2" lang="en"><a name="id2535340"></a><h3>void *talloc_memdup(const void *<span class="italic">ctx</span>, const void *<span class="italic">p</span>, size_t size);</h3><p>
341 The talloc_memdup() function is equivalent to:
342 </p><pre class="programlisting">ptr = talloc_size(ctx, size);
343 if (ptr) memcpy(ptr, p, size);</pre></div><div class="refsect2" lang="en"><a name="id2535369"></a><h3>char *talloc_strdup(const void *<span class="italic">ctx</span>, const char *<span class="italic">p</span>);</h3><p>
344 The talloc_strdup() function is equivalent to:
345 </p><pre class="programlisting">ptr = talloc_size(ctx, strlen(p)+1);
346 if (ptr) memcpy(ptr, p, strlen(p)+1);</pre><p>
347 This function sets the name of the new pointer to the passed
348 string. This is equivalent to:
349 </p><pre class="programlisting">talloc_set_name_const(ptr, ptr)</pre></div><div class="refsect2" lang="en"><a name="id2535409"></a><h3>char *talloc_strndup(const void *<span class="italic">t</span>, const char *<span class="italic">p</span>, size_t <span class="italic">n</span>);</h3><p>
350 The talloc_strndup() function is the talloc equivalent of the C
351 library function strndup(3).
353 This function sets the name of the new pointer to the passed
354 string. This is equivalent to:
355 </p><pre class="programlisting">talloc_set_name_const(ptr, ptr)</pre></div><div class="refsect2" lang="en"><a name="id2535449"></a><h3>char *talloc_append_string(const void *<span class="italic">t</span>, char *<span class="italic">orig</span>, const char *<span class="italic">append</span>);</h3><p>
356 The talloc_append_string() function appends the given formatted
357 string to the given string.
359 This function sets the name of the new pointer to the new
360 string. This is equivalent to:
361 </p><pre class="programlisting">talloc_set_name_const(ptr, ptr)</pre></div><div class="refsect2" lang="en"><a name="id2535489"></a><h3>char *talloc_vasprintf(const void *<span class="italic">t</span>, const char *<span class="italic">fmt</span>, va_list <span class="italic">ap</span>);</h3><p>
362 The talloc_vasprintf() function is the talloc equivalent of the C
363 library function vasprintf(3).
365 This function sets the name of the new pointer to the new
366 string. This is equivalent to:
367 </p><pre class="programlisting">talloc_set_name_const(ptr, ptr)</pre></div><div class="refsect2" lang="en"><a name="id2535528"></a><h3>char *talloc_asprintf(const void *<span class="italic">t</span>, const char *<span class="italic">fmt</span>, ...);</h3><p>
368 The talloc_asprintf() function is the talloc equivalent of the C
369 library function asprintf(3).
371 This function sets the name of the new pointer to the passed
372 string. This is equivalent to:
373 </p><pre class="programlisting">talloc_set_name_const(ptr, ptr)</pre></div><div class="refsect2" lang="en"><a name="id2535562"></a><h3>char *talloc_asprintf_append(char *s, const char *fmt, ...);</h3><p>
374 The talloc_asprintf_append() function appends the given formatted
375 string to the given string.
377 This function sets the name of the new pointer to the new
378 string. This is equivalent to:
379 </p><pre class="programlisting">talloc_set_name_const(ptr, ptr)</pre></div><div class="refsect2" lang="en"><a name="id2535586"></a><h3>(type *)talloc_array(const void *ctx, type, uint_t count);</h3><p>
380 The talloc_array() macro is equivalent to:
381 </p><pre class="programlisting">(type *)talloc_size(ctx, sizeof(type) * count);</pre><p>
382 except that it provides integer overflow protection for the
383 multiply, returning NULL if the multiply overflows.
384 </p></div><div class="refsect2" lang="en"><a name="id2535608"></a><h3>void *talloc_array_size(const void *ctx, size_t size, uint_t count);</h3><p>
385 The talloc_array_size() function is useful when the type is not
386 known. It operates in the same way as talloc_array(), but takes a
387 size instead of a type.
388 </p></div><div class="refsect2" lang="en"><a name="id2535621"></a><h3>(typeof(ptr)) talloc_array_ptrtype(const void *ctx, ptr, uint_t count);</h3><p>
389 The talloc_ptrtype() macro should be used when you have a pointer to an array
390 and want to allocate memory of an array to point at with this pointer. When compiling
391 with gcc >= 3 it is typesafe. Note this is a wrapper of talloc_array_size()
392 and talloc_get_name() will return the current location in the source file.
394 </p></div><div class="refsect2" lang="en"><a name="id2535637"></a><h3>void *talloc_realloc_fn(const void *ctx, void *ptr, size_t size)</h3><p>
395 This is a non-macro version of talloc_realloc(), which is useful
396 as libraries sometimes want a realloc function pointer. A
397 realloc(3) implementation encapsulates the functionality of
398 malloc(3), free(3) and realloc(3) in one call, which is why it is
399 useful to be able to pass around a single function pointer.
400 </p></div><div class="refsect2" lang="en"><a name="id2535653"></a><h3>void *talloc_autofree_context(void);</h3><p>
401 This is a handy utility function that returns a talloc context
402 which will be automatically freed on program exit. This can be
403 used to reduce the noise in memory leak reports.
404 </p></div><div class="refsect2" lang="en"><a name="id2535665"></a><h3>void *talloc_check_name(const void *ptr, const char *name);</h3><p>
405 This function checks if a pointer has the specified <span class="italic">name</span>. If it does then the pointer is
406 returned. It it doesn't then NULL is returned.
407 </p></div><div class="refsect2" lang="en"><a name="id2535683"></a><h3>(type *)talloc_get_type(const void *ptr, type);</h3><p>
408 This macro allows you to do type checking on talloc pointers. It
409 is particularly useful for void* private pointers. It is
411 </p><pre class="programlisting">(type *)talloc_check_name(ptr, #type)</pre></div><div class="refsect2" lang="en"><a name="id2535702"></a><h3>talloc_set_type(const void *ptr, type);</h3><p>
412 This macro allows you to force the name of a pointer to be a
413 particular <span class="emphasis"><em>type</em></span>. This can be
414 used in conjunction with talloc_get_type() to do type checking on
417 It is equivalent to this:
418 </p><pre class="programlisting">talloc_set_name_const(ptr, #type)</pre></div></div><div class="refsect1" lang="en"><a name="id2535730"></a><h2>PERFORMANCE</h2><p>
419 All the additional features of talloc(3) over malloc(3) do come at a
420 price. We have a simple performance test in Samba4 that measures
421 talloc() versus malloc() performance, and it seems that talloc() is
422 about 10% slower than malloc() on my x86 Debian Linux box. For
423 Samba, the great reduction in code complexity that we get by using
424 talloc makes this worthwhile, especially as the total overhead of
425 talloc/malloc in Samba is already quite small.
426 </p></div><div class="refsect1" lang="en"><a name="id2535755"></a><h2>SEE ALSO</h2><p>
427 malloc(3), strndup(3), vasprintf(3), asprintf(3),
428 <a href="http://talloc.samba.org/" target="_top">http://talloc.samba.org/</a>
429 </p></div><div class="refsect1" lang="en"><a name="id2535770"></a><h2>COPYRIGHT/LICENSE</h2><p>
430 Copyright (C) Andrew Tridgell 2004
432 This program is free software; you can redistribute it and/or modify
433 it under the terms of the GNU General Public License as published by
434 the Free Software Foundation; either version 3 of the License, or (at
435 your option) any later version.
437 This program is distributed in the hope that it will be useful, but
438 WITHOUT ANY WARRANTY; without even the implied warranty of
439 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
440 General Public License for more details.
442 You should have received a copy of the GNU General Public License
443 along with this program; if not, see http://www.gnu.org/licenses/.
444 </p></div></div></body></html>