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34 <!--*********************************************************************-->
35 <h1>Type traits intrinsic design</h1>
36 <!--*********************************************************************-->
37
38<p>
39This is a survey of the type traits intrinsics clang has, and those needed.
40The names and definitions of several of the needed type traits has recently
41changed. Please see:
42<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2010/n3142.html">N3142</a>.
43</p>
44
45<blockquote>
46<table border="1">
47<caption>Legend</caption>
48
49<tr>
50<td>clang supplies it and it is absolutely necessary</td>
51<td bgcolor="#80FF80"><tt>some_trait(T)</tt></td>
52</tr>
53
54<tr>
55<td>clang supplies it and it is useful</td>
56<td bgcolor="#96B9FF"><tt>some_trait(T)</tt></td>
57</tr>
58
59<tr>
60<td>clang supplies it and it is not needed</td>
61<td><tt>some_trait(T)</tt></td>
62</tr>
63
64<tr>
65<td>clang does not supply it and it is not needed</td>
66<td></td>
67</tr>
68
69<tr>
70<td>clang does not supply it and it is absolutely necessary</td>
71<td bgcolor="#FF5965"><tt>some_trait(T)</tt></td>
72</tr>
73
74</table>
75
76<p></p>
77
78<table border="1">
79<caption>Needed type traits vs clang type traits</caption>
80
81<tr>
82<th>libc++ Needs</th>
83<th>clang Has</th>
84</tr>
85
86<tr>
87<td><tt>is_union&lt;T&gt;</tt></td>
88<td bgcolor="#80FF80"><tt>__is_union(T)</tt></td>
89</tr>
90
91<tr>
92<td><tt>is_class&lt;T&gt;</tt></td>
93<td bgcolor="#96B9FF"><tt>__is_class(T)</tt></td>
94</tr>
95
96<tr>
97<td><tt>is_enum&lt;T&gt;</tt></td>
98<td bgcolor="#96B9FF"><tt>__is_enum(T)</tt></td>
99</tr>
100
101<tr>
102<td><tt>is_pod&lt;T&gt;</tt></td>
103<td bgcolor="#80FF80"><tt>__is_pod(T)</tt></td>
104</tr>
105
106<tr>
107<td><tt>has_virtual_destructor&lt;T&gt;</tt></td>
108<td bgcolor="#80FF80"><tt>__has_virtual_destructor(T)</tt></td>
109</tr>
110
111<tr>
112<td><tt>is_constructible&lt;T, Args...&gt;</tt></td>
Howard Hinnant7bbce3c2011-05-13 00:01:01 +0000[diff] [blame]113<td></td>
Howard Hinnant9835d762010-11-19 01:38:58 +0000[diff] [blame]114</tr>
115
116<tr>
117<td><tt>is_default_constructible&lt;T&gt;</tt></td>
118<td></td>
119</tr>
120
121<tr>
122<td><tt>is_copy_constructible&lt;T&gt;</tt></td>
123<td></td>
124</tr>
125
126<tr>
127<td><tt>is_move_constructible&lt;T&gt;</tt></td>
128<td></td>
129</tr>
130
131<tr>
132<td><tt>is_assignable&lt;T, U&gt;</tt></td>
Howard Hinnant7bbce3c2011-05-13 00:01:01 +0000[diff] [blame]133<td></td>
Howard Hinnant9835d762010-11-19 01:38:58 +0000[diff] [blame]134</tr>
135
136<tr>
137<td><tt>is_copy_assignable&lt;T&gt;</tt></td>
138<td></td>
139</tr>
140
141<tr>
142<td><tt>is_move_assignable&lt;T&gt;</tt></td>
143<td></td>
144</tr>
145
146<tr>
147<td><tt>is_destructible&lt;T&gt;</tt></td>
Howard Hinnant0cfa1f72011-05-13 13:39:08 +0000[diff] [blame]148<td></td>
Howard Hinnant9835d762010-11-19 01:38:58 +0000[diff] [blame]149</tr>
150
151<tr>
152<td><tt>is_trivially_constructible&lt;T, Args...&gt;</tt></td>
Howard Hinnant7d87f6b2012-07-19 15:59:52 +0000[diff] [blame]153<td bgcolor="#80FF80"><tt>__is_trivially_constructible(T, U)</tt></td>
Howard Hinnant9835d762010-11-19 01:38:58 +0000[diff] [blame]154</tr>
155
156<tr>
157<td><tt>is_trivially_default_constructible&lt;T&gt;</tt></td>
Howard Hinnant7bbce3c2011-05-13 00:01:01 +0000[diff] [blame]158<td bgcolor="#80FF80"><tt>__has_trivial_constructor(T)</tt></td>
Howard Hinnant9835d762010-11-19 01:38:58 +0000[diff] [blame]159</tr>
160
161<tr>
162<td><tt>is_trivially_copy_constructible&lt;T&gt;</tt></td>
163<td><tt>__has_trivial_copy(T)</tt></td>
164</tr>
165
166<tr>
167<td><tt>is_trivially_move_constructible&lt;T&gt;</tt></td>
168<td></td>
169</tr>
170
171<tr>
172<td><tt>is_trivially_assignable&lt;T, U&gt;</tt></td>
Howard Hinnant7d87f6b2012-07-19 15:59:52 +0000[diff] [blame]173<td bgcolor="#80FF80"><tt>__is_trivially_assignable(T, U)</tt></td>
Howard Hinnant9835d762010-11-19 01:38:58 +0000[diff] [blame]174</tr>
175
176<tr>
177<td><tt>is_trivially_copy_assignable&lt;T&gt;</tt></td>
178<td><tt>__has_trivial_assign(T)</tt></td>
179</tr>
180
181<tr>
182<td><tt>is_trivially_move_assignable&lt;T&gt;</tt></td>
183<td></td>
184</tr>
185
186<tr>
187<td><tt>is_trivially_destructible&lt;T&gt;</tt></td>
188<td bgcolor="#80FF80"><tt>__has_trivial_destructor(T)</tt></td>
189</tr>
190
191<tr>
192<td><tt>is_nothrow_constructible&lt;T, Args...&gt;</tt></td>
Howard Hinnant7bbce3c2011-05-13 00:01:01 +0000[diff] [blame]193<td></td>
Howard Hinnant9835d762010-11-19 01:38:58 +0000[diff] [blame]194</tr>
195
196<tr>
197<td><tt>is_nothrow_default_constructible&lt;T&gt;</tt></td>
198<td><tt>__has_nothrow_constructor(T)</tt></td>
199</tr>
200
201<tr>
202<td><tt>is_nothrow_copy_constructible&lt;T&gt;</tt></td>
203<td><tt>__has_nothrow_copy(T)</tt></td>
204</tr>
205
206<tr>
207<td><tt>is_nothrow_move_constructible&lt;T&gt;</tt></td>
208<td></td>
209</tr>
210
211<tr>
212<td><tt>is_nothrow_assignable&lt;T, U&gt;</tt></td>
Howard Hinnant7bbce3c2011-05-13 00:01:01 +0000[diff] [blame]213<td></td>
Howard Hinnant9835d762010-11-19 01:38:58 +0000[diff] [blame]214</tr>
215
216<tr>
217<td><tt>is_nothrow_copy_assignable&lt;T&gt;</tt></td>
218<td><tt>__has_nothrow_assign(T)</tt></td>
219</tr>
220
221<tr>
222<td><tt>is_nothrow_move_assignable&lt;T&gt;</tt></td>
223<td></td>
224</tr>
225
226<tr>
227<td><tt>is_nothrow_destructible&lt;T&gt;</tt></td>
Howard Hinnant0cfa1f72011-05-13 13:39:08 +0000[diff] [blame]228<td></td>
Howard Hinnant9835d762010-11-19 01:38:58 +0000[diff] [blame]229</tr>
230
Howard Hinnant01feecb2010-11-19 01:48:13 +0000[diff] [blame]231<tr>
232<td><tt>is_trivial&lt;T&gt;</tt></td>
Howard Hinnant7bbce3c2011-05-13 00:01:01 +0000[diff] [blame]233<td bgcolor="#80FF80"><tt>__is_trivial(T)</tt></td>
Howard Hinnant01feecb2010-11-19 01:48:13 +0000[diff] [blame]234</tr>
235
236<tr>
237<td><tt>is_trivially_copyable&lt;T&gt;</tt></td>
Sean Hunt9e604b42011-05-13 00:32:09 +0000[diff] [blame]238<td bgcolor="#80FF80"><tt>__is_trivially_copyable(T)</tt></td>
Howard Hinnant01feecb2010-11-19 01:48:13 +0000[diff] [blame]239</tr>
240
241<tr>
242<td><tt>is_standard_layout&lt;T&gt;</tt></td>
Howard Hinnant7bbce3c2011-05-13 00:01:01 +0000[diff] [blame]243<td bgcolor="#80FF80"><tt>__is_standard_layout(T)</tt></td>
Howard Hinnant01feecb2010-11-19 01:48:13 +0000[diff] [blame]244</tr>
245
246<tr>
247<td><tt>is_literal_type&lt;T&gt;</tt></td>
Howard Hinnant36666952011-05-09 19:21:17 +0000[diff] [blame]248<td bgcolor="#80FF80"><tt>__is_literal_type(T)</tt></td>
Howard Hinnant01feecb2010-11-19 01:48:13 +0000[diff] [blame]249</tr>
250
251<tr>
252<td><tt>is_convertible&lt;T, U&gt;</tt></td>
Howard Hinnant36666952011-05-09 19:21:17 +0000[diff] [blame]253<td bgcolor="#80FF80"><tt>__is_convertible_to(T, U)</tt></td>
Howard Hinnant01feecb2010-11-19 01:48:13 +0000[diff] [blame]254</tr>
255
256<tr>
257<td><tt>is_base_of&lt;T, U&gt;</tt></td>
Howard Hinnant86e78d62011-03-26 19:58:42 +0000[diff] [blame]258<td bgcolor="#80FF80"><tt>__is_base_of(T, U)</tt></td>
Howard Hinnant01feecb2010-11-19 01:48:13 +0000[diff] [blame]259</tr>
260
261<tr>
262<td><tt>underlying_type&lt;T&gt;</tt></td>
Sean Hunt737a3512011-07-18 18:37:21 +0000[diff] [blame]263<td bgcolor="#80FF80"><tt>__underlying_type(T)</tt></td>
Howard Hinnant01feecb2010-11-19 01:48:13 +0000[diff] [blame]264</tr>
265
Howard Hinnant36666952011-05-09 19:21:17 +0000[diff] [blame]266<tr>
267<td><tt>is_polymorphic&lt;T&gt;</tt></td>
268<td><tt>__is_polymorphic(T)</tt></td>
269</tr>
270
271<tr>
272<td><tt>is_empty&lt;T&gt;</tt></td>
273<td><tt>__is_empty(T)</tt></td>
274</tr>
275
276<tr>
277<td><tt>is_abstract&lt;T&gt;</tt></td>
278<td><tt>__is_abstract(T)</tt></td>
279</tr>
280
Howard Hinnant9835d762010-11-19 01:38:58 +0000[diff] [blame]281</table>
282</blockquote>
283
284</div>
285</body>
286</html>