1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
|
<!DOCTYPE html>
<html lang="en" dir="ltr" class="client-nojs">
<head>
<title>Function-try-block - cppreference.com</title>
<meta charset="UTF-8" />
<meta name="generator" content="MediaWiki 1.21.2" />
<link rel="alternate" type="application/x-wiki" title="Edit" href="http://en.cppreference.com/mwiki/index.php?title=cpp/language/function-try-block&action=edit" />
<link rel="edit" title="Edit" href="http://en.cppreference.com/mwiki/index.php?title=cpp/language/function-try-block&action=edit" />
<link rel="shortcut icon" href="../../../favicon.ico" />
<link rel="search" type="application/opensearchdescription+xml" href="../../../mwiki/opensearch_desc.php" title="cppreference.com (en)" />
<link rel="EditURI" type="application/rsd+xml" href="http://en.cppreference.com/mwiki/api.php?action=rsd" />
<link rel="alternate" type="application/atom+xml" title="cppreference.com Atom feed" href="http://en.cppreference.com/mwiki/index.php?title=Special:RecentChanges&feed=atom" />
<link rel="stylesheet" href="../../../mwiki/load.php%3Fdebug=false&lang=en&modules=ext.gadget.ColiruCompiler%257Cext.rtlcite%257Cmediawiki.legacy.commonPrint%252Cshared%257Cskins.cppreference2&only=styles&skin=cppreference2&*.css" />
<meta name="ResourceLoaderDynamicStyles" content="" />
<link rel="stylesheet" href="../../../mwiki/load.php%3Fdebug=false&lang=en&modules=site&only=styles&skin=cppreference2&*.css" />
<style>a:lang(ar),a:lang(ckb),a:lang(fa),a:lang(kk-arab),a:lang(mzn),a:lang(ps),a:lang(ur){text-decoration:none}#toc{display:none}.editsection{display:none}
/* cache key: mwiki1-mwiki_en_:resourceloader:filter:minify-css:7:472787eddcf4605d11de8c7ef047234f */</style>
<script src="../../../mwiki/load.php%3Fdebug=false&lang=en&modules=startup&only=scripts&skin=cppreference2&*"></script>
<script>if(window.mw){
mw.config.set({"wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"cpp/language/function-try-block","wgTitle":"cpp/language/function-try-block","wgCurRevisionId":69262,"wgArticleId":13494,"wgIsArticle":true,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":[],"wgBreakFrames":false,"wgPageContentLanguage":"en","wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy","wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgMonthNamesShort":["","Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"],"wgRelevantPageName":"cpp/language/function-try-block","wgRestrictionEdit":[],"wgRestrictionMove":[]});
}</script><script>if(window.mw){
mw.loader.implement("user.options",function(){mw.user.options.set({"ccmeonemails":0,"cols":80,"date":"default","diffonly":0,"disablemail":0,"disablesuggest":0,"editfont":"default","editondblclick":0,"editsection":0,"editsectiononrightclick":0,"enotifminoredits":0,"enotifrevealaddr":0,"enotifusertalkpages":1,"enotifwatchlistpages":0,"extendwatchlist":0,"externaldiff":0,"externaleditor":0,"fancysig":0,"forceeditsummary":0,"gender":"unknown","hideminor":0,"hidepatrolled":0,"imagesize":2,"justify":0,"math":1,"minordefault":0,"newpageshidepatrolled":0,"nocache":0,"noconvertlink":0,"norollbackdiff":0,"numberheadings":0,"previewonfirst":0,"previewontop":1,"quickbar":5,"rcdays":7,"rclimit":50,"rememberpassword":0,"rows":25,"searchlimit":20,"showhiddencats":0,"showjumplinks":1,"shownumberswatching":1,"showtoc":0,"showtoolbar":1,"skin":"cppreference2","stubthreshold":0,"thumbsize":2,"underline":2,"uselivepreview":0,"usenewrc":0,"watchcreations":0,"watchdefault":0,"watchdeletion":0,
"watchlistdays":3,"watchlisthideanons":0,"watchlisthidebots":0,"watchlisthideliu":0,"watchlisthideminor":0,"watchlisthideown":0,"watchlisthidepatrolled":0,"watchmoves":0,"wllimit":250,"variant":"en","language":"en","searchNs0":true,"searchNs1":false,"searchNs2":false,"searchNs3":false,"searchNs4":false,"searchNs5":false,"searchNs6":false,"searchNs7":false,"searchNs8":false,"searchNs9":false,"searchNs10":false,"searchNs11":false,"searchNs12":false,"searchNs13":false,"searchNs14":false,"searchNs15":false,"gadget-ColiruCompiler":1});;},{},{});mw.loader.implement("user.tokens",function(){mw.user.tokens.set({"editToken":"+\\","patrolToken":false,"watchToken":false});;},{},{});
/* cache key: mwiki1-mwiki_en_:resourceloader:filter:minify-js:7:ca03345b1e2c4d90a25d968753a73b92 */
}</script>
<script>if(window.mw){
mw.loader.load(["mediawiki.page.startup","mediawiki.legacy.wikibits","mediawiki.legacy.ajax"]);
}</script>
<style type="text/css">/*<![CDATA[*/
.source-cpp {line-height: normal;}
.source-cpp li, .source-cpp pre {
line-height: normal; border: 0px none white;
}
/**
* GeSHi Dynamically Generated Stylesheet
* --------------------------------------
* Dynamically generated stylesheet for cpp
* CSS class: source-cpp, CSS id:
* GeSHi (C) 2004 - 2007 Nigel McNie, 2007 - 2008 Benny Baumann
* (http://qbnz.com/highlighter/ and http://geshi.org/)
* --------------------------------------
*/
.cpp.source-cpp .de1, .cpp.source-cpp .de2 {font: normal normal 1em/1.2em monospace; margin:0; padding:0; background:none; vertical-align:top;}
.cpp.source-cpp {font-family:monospace;}
.cpp.source-cpp .imp {font-weight: bold; color: red;}
.cpp.source-cpp li, .cpp.source-cpp .li1 {font-weight: normal; vertical-align:top;}
.cpp.source-cpp .ln {width:1px;text-align:right;margin:0;padding:0 2px;vertical-align:top;}
.cpp.source-cpp .li2 {font-weight: bold; vertical-align:top;}
.cpp.source-cpp .kw1 {color: #0000dd;}
.cpp.source-cpp .kw2 {color: #0000ff;}
.cpp.source-cpp .kw3 {color: #0000dd;}
.cpp.source-cpp .kw4 {color: #0000ff;}
.cpp.source-cpp .co1 {color: #909090;}
.cpp.source-cpp .co2 {color: #339900;}
.cpp.source-cpp .coMULTI {color: #ff0000; font-style: italic;}
.cpp.source-cpp .es0 {color: #008000; font-weight: bold;}
.cpp.source-cpp .es1 {color: #008000; font-weight: bold;}
.cpp.source-cpp .es2 {color: #008000; font-weight: bold;}
.cpp.source-cpp .es3 {color: #008000; font-weight: bold;}
.cpp.source-cpp .es4 {color: #008000; font-weight: bold;}
.cpp.source-cpp .es5 {color: #008000; font-weight: bold;}
.cpp.source-cpp .br0 {color: #008000;}
.cpp.source-cpp .sy0 {color: #008000;}
.cpp.source-cpp .sy1 {color: #000080;}
.cpp.source-cpp .sy2 {color: #000040;}
.cpp.source-cpp .sy3 {color: #000040;}
.cpp.source-cpp .sy4 {color: #008080;}
.cpp.source-cpp .st0 {color: #008000;}
.cpp.source-cpp .nu0 {color: #000080;}
.cpp.source-cpp .nu6 {color: #000080;}
.cpp.source-cpp .nu8 {color: #000080;}
.cpp.source-cpp .nu12 {color: #000080;}
.cpp.source-cpp .nu16 {color:#000080;}
.cpp.source-cpp .nu17 {color:#000080;}
.cpp.source-cpp .nu18 {color:#000080;}
.cpp.source-cpp .nu19 {color:#000080;}
.cpp.source-cpp .ln-xtra, .cpp.source-cpp li.ln-xtra, .cpp.source-cpp div.ln-xtra {background-color: #ffc;}
.cpp.source-cpp span.xtra { display:block; }
/*]]>*/
</style><!--[if lt IE 7]><style type="text/css">body{behavior:url("/mwiki/skins/cppreference2/csshover.min.htc")}</style><![endif]--></head>
<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_language_function-try-block skin-cppreference2 action-view cpp-navbar">
<!-- header -->
<div id="mw-head" class="noprint">
<div id="cpp-head-first-base">
<div id="cpp-head-first">
<h5><a href="../../../index.html">
cppreference.com </a></h5>
<div id="cpp-head-search">
<!-- 0 -->
<div id="p-search">
<h5><label for="searchInput">Search</label></h5>
<form action="http://en.cppreference.com/mwiki/index.php" id="searchform">
<input type='hidden' name="title" value="Special:Search"/>
<div id="simpleSearch">
<input name="search" title="Search cppreference.com [f]" accesskey="f" id="searchInput" /> <button type="submit" name="button" title="Search the pages for this text" id="searchButton"><img src="../../../mwiki/skins/cppreference2/images/search-ltr.png%3F303" alt="Search" /></button> </div>
</form>
</div>
<!-- /0 -->
</div>
<div id="cpp-head-personal">
<!-- 0 -->
<div id="p-personal" class="">
<span id="pt-createaccount"><a href="http://en.cppreference.com/mwiki/index.php?title=Special:UserLogin&returnto=cpp%2Flanguage%2Ffunction-try-block&type=signup">Create account</a></span> <div class="menu">
<ul>
<li id="pt-login"><a href="http://en.cppreference.com/mwiki/index.php?title=Special:UserLogin&returnto=cpp%2Flanguage%2Ffunction-try-block" title="You are encouraged to log in; however, it is not mandatory [o]" accesskey="o">Log in</a></li> </ul>
</div>
</div>
<!-- /0 -->
</div>
</div>
</div>
<div id="cpp-head-second-base">
<div id="cpp-head-second">
<div id="cpp-head-tools-left">
<!-- 0 -->
<div id="p-namespaces" class="vectorTabs">
<h5>Namespaces</h5>
<ul>
<li id="ca-nstab-main" class="selected"><span><a href="function-try-block.html" title="View the content page [c]" accesskey="c">Page</a></span></li>
<li id="ca-talk"><span><a href="http://en.cppreference.com/w/Talk:cpp/language/function-try-block" title="Discussion about the content page [t]" accesskey="t">Discussion</a></span></li>
</ul>
</div>
<!-- /0 -->
<!-- 1 -->
<div id="p-variants" class="vectorMenu emptyPortlet">
<h5><span>Variants</span><a href="function-try-block.html#"></a></h5>
<div class="menu">
<ul>
</ul>
</div>
</div>
<!-- /1 -->
</div>
<div id="cpp-head-tools-right">
<!-- 0 -->
<div id="p-views" class="vectorTabs">
<h5>Views</h5>
<ul>
<li id="ca-view" class="selected"><span><a href="function-try-block.html" >View</a></span></li>
<li id="ca-edit"><span><a href="http://en.cppreference.com/mwiki/index.php?title=cpp/language/function-try-block&action=edit" title="You can edit this page. Please use the preview button before saving [e]" accesskey="e">Edit</a></span></li>
<li id="ca-history" class="collapsible"><span><a href="http://en.cppreference.com/mwiki/index.php?title=cpp/language/function-try-block&action=history" title="Past revisions of this page [h]" accesskey="h">History</a></span></li>
</ul>
</div>
<!-- /0 -->
<!-- 1 -->
<div id="p-cactions" class="vectorMenu emptyPortlet">
<h5><span>Actions</span><a href="function-try-block.html#"></a></h5>
<div class="menu">
<ul>
</ul>
</div>
</div>
<!-- /1 -->
</div>
</div>
</div>
</div>
<!-- /header -->
<!-- content -->
<div id="cpp-content-base">
<div id="content">
<a id="top"></a>
<div id="mw-js-message" style="display:none;"></div>
<!-- firstHeading -->
<h1 id="firstHeading" class="firstHeading">Function-try-block</h1>
<!-- /firstHeading -->
<!-- bodyContent -->
<div id="bodyContent">
<!-- tagline -->
<div id="siteSub">From cppreference.com</div>
<!-- /tagline -->
<!-- subtitle -->
<div id="contentSub"><span class="subpages">< <a href="../../cpp.html" title="cpp">cpp</a>‎ | <a href="../language.1.html" title="cpp/language">language</a></span></div>
<!-- /subtitle -->
<!-- bodycontent -->
<div id="mw-content-text" lang="en" dir="ltr" class="mw-content-ltr"><div class="t-navbar" style=""><div class="t-navbar-sep"> </div><div class="t-navbar-head"><a href="../../cpp.html" title="cpp"> C++</a><div class="t-navbar-menu"><div><div><table class="t-nv-begin" cellpadding="0" style="line-height:1.1em;">
<tr class="t-nv"><td colspan="5"> <a href="../language.1.html" title="cpp/language"> Language</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../header.html" title="cpp/header"> Standard library headers</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../concept.html" title="cpp/concept"> Concepts</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../utility.html" title="cpp/utility"> Utilities library</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../string.html" title="cpp/string"> Strings library</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../container.html" title="cpp/container"> Containers library</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../algorithm.html" title="cpp/algorithm"> Algorithms library</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../iterator.html" title="cpp/iterator"> Iterators library</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../numeric.html" title="cpp/numeric"> Numerics library</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../io.html" title="cpp/io"> Input/output library</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../locale.html" title="cpp/locale"> Localizations library</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../regex.html" title="cpp/regex"> Regular expressions library</a> <span class="t-mark-rev t-since-cxx11">(C++11)</span> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../atomic.html" title="cpp/atomic"> Atomic operations library</a> <span class="t-mark-rev t-since-cxx11">(C++11)</span> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../thread.html" title="cpp/thread"> Thread support library</a> <span class="t-mark-rev t-since-cxx11">(C++11)</span> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../experimental.html" title="cpp/experimental"> Technical Specifications</a> </td></tr>
</table></div><div><span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/navbar_content&action=edit">[edit]</a></span></div></div></div></div><div class="t-navbar-sep"> </div><div class="t-navbar-head"><a href="../language.1.html" title="cpp/language"> C++ language</a></div><div class="t-navbar-sep"> </div><div class="t-navbar-head"><a href="exceptions.html" title="cpp/language/exceptions"> Exceptions</a><div class="t-navbar-menu"><div><div style="display:inline-block">
<div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"> <a href="throw.html" title="cpp/language/throw"> throw-expression</a></td></tr>
<tr class="t-nv"><td colspan="5"> <strong class="selflink"> function-try-block</strong></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="try_catch.html" title="cpp/language/try catch"> try/catch block</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="noexcept_spec.html" title="cpp/language/noexcept spec"> noexcept specifier</a><span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="noexcept.html" title="cpp/language/noexcept"> noexcept operator</a><span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="except_spec.html" title="cpp/language/except spec"> exception-specification</a><span class="t-mark">(deprecated)</span></td></tr>
</table></div>
</div><div><span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/language/exceptions/navbar_content&action=edit">[edit]</a></span></div></div></div></div><div class="t-navbar-sep"> </div></div>
<p>Establishes an exception handler around the body of a function.
</p>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/language/function-try-block&action=edit&section=1" title="Edit section: Syntax">edit</a>]</span> <span class="mw-headline" id="Syntax">Syntax</span></h3>
<p>The function-try-block is one of the alternative syntax forms for <span class="t-spar">function-body</span>, which is a part of <a href="function.html" title="cpp/language/function">function definition</a>.
</p>
<table class="t-sdsc-begin">
<tr>
<td colspan="10" class="t-sdsc-sep">
</td></tr>
<tr class="t-sdsc">
<td class="t-sdsc-nopad"> <code><b>try</b></code> <span class="t-spar">ctor-initializer</span><span class="t-mark">(optional)</span> <span class="t-spar">compound-statement</span> <span class="t-spar">handler-sequence</span>
</td>
<td class="t-sdsc-nopad">
</td>
<td class="t-sdsc-nopad">
</td></tr>
<tr>
<td colspan="10" class="t-sdsc-sep">
</td></tr></table>
<table class="t-par-begin">
<tr class="t-par">
<td> <span class="t-spar">ctor-initializer</span>
</td>
<td> -
</td>
<td> member <a href="constructor.html" title="cpp/language/initializer list">initializer list</a>, only allowed in constructors
</td></tr>
<tr class="t-par">
<td> <span class="t-spar">compound-statement</span>
</td>
<td> -
</td>
<td> the brace-enclosed <a href="statements.html#Compound_statement" title="cpp/language/statements">sequence of statements</a> that constututes the body of a function
</td></tr>
<tr class="t-par">
<td> <span class="t-spar">handler-sequence</span>
</td>
<td> -
</td>
<td> sequence of one or more <a href="try_catch.html" title="cpp/language/try catch">catch-clauses</a>
</td></tr></table>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/language/function-try-block&action=edit&section=2" title="Edit section: Explanation">edit</a>]</span> <span class="mw-headline" id="Explanation">Explanation</span></h3>
<p>A <i>function-try-block</i> associates a sequence of catch clauses with the entire function body, and with the <a href="constructor.html" title="cpp/language/initializer list">member initializer list</a> (if used in a constructor) as well. Every exception thrown from any statement in the function body, or (for constructors) from any member or base constructor, or (for destructors) from any member or base destructor, transfers control to the <span class="t-spar">handler-sequence</span> the same way an exception thrown in a regular <a href="try_catch.html" title="cpp/language/try catch">try block</a> would.
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">struct</span> S <span class="br0">{</span>
<a href="../string/basic_string.html"><span class="kw1042">std::<span class="me2">string</span></span></a> m<span class="sy4">;</span>
S<span class="br0">(</span><span class="kw4">const</span> <a href="../string/basic_string.html"><span class="kw1042">std::<span class="me2">string</span></span></a><span class="sy3">&</span> arg<span class="br0">)</span> <span class="kw1">try</span> <span class="sy4">:</span> m<span class="br0">(</span>arg, <span class="nu0">100</span><span class="br0">)</span> <span class="br0">{</span>
<a href="../io/cout.html"><span class="kw1446">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"constructed, mn = "</span> <span class="sy1"><<</span> m <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
<span class="br0">}</span> <span class="kw1">catch</span><span class="br0">(</span><span class="kw4">const</span> <a href="../error/exception.html"><span class="kw611">std::<span class="me2">exception</span></span></a><span class="sy3">&</span> e<span class="br0">)</span> <span class="br0">{</span>
<a href="../io/cerr.html"><span class="kw1448">std::<span class="me2">cerr</span></span></a> <span class="sy1"><<</span> <span class="st0">"arg="</span> <span class="sy1"><<</span> arg <span class="sy1"><<</span> <span class="st0">" failed: "</span> <span class="sy1"><<</span> e.<span class="me1">what</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
<span class="br0">}</span> <span class="co1">// implicit throw; here</span>
<span class="br0">}</span><span class="sy4">;</span></pre></div></div>
<p>Before any catch clauses of a function-try-block on a constructor are entered, all fully-constructed members and bases have already been destroyed.
</p>
<table class="t-rev-begin">
<tr class="t-rev t-since-cxx11"><td> If the function-try-block is on a delegating constructor, which called a non-delegating constructor that completed successfully, but then the body of the delegating constructor throws, the destructor of this object will be completed before any catch clauses of the function-try-block are entered.</td>
<td><span class="t-mark-rev t-since-cxx11">(since C++11)</span></td></tr>
</table>
<p>Before any catch clauses of a function-try-block on a destructor are entered, all bases and non-variant members have already been destroyed.
</p><p>The behavior is undefined if the catch-clause of a function-try-block used on a constructor or a destructor accesses a base or a non-static member of the object.
</p><p>Every catch-clause in the function-try-block for a constructor must terminate by throwing an exception. If the control reaches the end of such handler, the current exception is automatically rethrown as if by <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">throw</span><span class="sy4">;</span></span></span>. The return statement is not allowed in any catch clause of a constructor's function-try-block.
</p><p>Reaching the end of a catch clause for a function-try-block on a destructor also automatically rethrows the current exception as if by <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">throw</span><span class="sy4">;</span></span></span>, but a return statement is allowed.
</p><p>For all other functions, reaching the end of a catch clause is equivalent to <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">return</span><span class="sy4">;</span></span></span> (which means undefined behavior if the function is not returning <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">void</span></span></span>)
</p>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/language/function-try-block&action=edit&section=3" title="Edit section: Notes">edit</a>]</span> <span class="mw-headline" id="Notes">Notes</span></h3>
<p>The primary purpose of function-try-blocks is to log or modify, and then rethrow the exceptions thrown from the member initializer list in a constructor. They are rarely used with destructors or with regular functions.
</p><p>Function-try-block does not catch the exceptions thrown by the copy/move constructors and the destructors of the function parameters passed by value: those exceptions are thrown in context of the caller.
</p>
<table class="t-rev-begin">
<tr class="t-rev t-since-cxx11"><td>
Function-try-block of the top-level function of a thread does not catch the exceptions thrown from the constructors and destructors of <a href="storage_duration.html" title="cpp/language/storage duration">thread-local</a> objects (except for the constructors of function-scoped thread-locals). </td>
<td><span class="t-mark-rev t-since-cxx11">(since C++11)</span></td></tr>
</table>
<p>Likewise, function-try-block of the <a href="main_function.html" title="cpp/language/main function">main() function</a> does not catch the exceptions thrown from the constructors and destructors of <a href="storage_duration.html" title="cpp/language/storage duration">static</a> objects (except for the constructors of function-local statics).
</p><p><a href="scope.html#Block_scope" title="cpp/language/scope">The scope</a> and lifetime of the function parameters (but not any objects declared in the function itself), extend to the end of the <span class="t-spar">handler-sequence</span>.
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw4">int</span> f<span class="br0">(</span><span class="kw4">int</span> n <span class="sy1">=</span> <span class="nu0">2</span><span class="br0">)</span> <span class="kw1">try</span> <span class="br0">{</span>
<span class="sy2">++</span>n<span class="sy4">;</span> <span class="co1">// increments the function parameter</span>
<span class="kw1">throw</span> n<span class="sy4">;</span>
<span class="br0">}</span> <span class="kw1">catch</span><span class="br0">(</span>...<span class="br0">)</span> <span class="br0">{</span>
<span class="sy2">++</span>n<span class="sy4">;</span> <span class="co1">// n is in scope and still refers to the function parameter</span>
<a href="../error/assert.html"><span class="kw621">assert</span></a><span class="br0">(</span>n <span class="sy1">==</span> <span class="nu0">4</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw1">return</span> n<span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<!--
NewPP limit report
Preprocessor visited node count: 886/1000000
Preprocessor generated node count: 2897/1000000
Post‐expand include size: 23654/2097152 bytes
Template argument size: 4547/2097152 bytes
Highest expansion depth: 13/40
Expensive parser function count: 0/100
-->
<!-- Saved in parser cache with key mwiki1-mwiki_en_:pcache:idhash:13494-0!*!0!!*!*!* and timestamp 20150313165905 -->
</div> <!-- /bodycontent -->
<!-- printfooter -->
<div class="printfooter">
Retrieved from "<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/language/function-try-block&oldid=69262">http://en.cppreference.com/mwiki/index.php?title=cpp/language/function-try-block&oldid=69262</a>" </div>
<!-- /printfooter -->
<!-- catlinks -->
<div id='catlinks' class='catlinks catlinks-allhidden'></div> <!-- /catlinks -->
<div class="visualClear"></div>
<!-- debughtml -->
<!-- /debughtml -->
</div>
<!-- /bodyContent -->
</div>
</div>
<!-- /content -->
<!-- footer -->
<div id="cpp-footer-base" class="noprint">
<div id="footer">
<div id="cpp-navigation">
<h5>Navigation</h5>
<ul>
<li id="n-Support-us"><a href="http://www.cppreference.com/support" rel="nofollow">Support us</a></li><li id="n-recentchanges"><a href="http://en.cppreference.com/w/Special:RecentChanges" title="A list of recent changes in the wiki [r]" accesskey="r">Recent changes</a></li><li id="n-FAQ"><a href="http://en.cppreference.com/w/Cppreference:FAQ">FAQ</a></li><li id="n-Offline-version"><a href="http://en.cppreference.com/w/Cppreference:Archives">Offline version</a></li> </ul>
</div>
<div id="cpp-toolbox">
<h5><span>Toolbox</span><a href="function-try-block.html#"></a></h5>
<ul>
<li id="t-whatlinkshere"><a href="http://en.cppreference.com/w/Special:WhatLinksHere/cpp/language/function-try-block" title="A list of all wiki pages that link here [j]" accesskey="j">What links here</a></li><li id="t-recentchangeslinked"><a href="http://en.cppreference.com/w/Special:RecentChangesLinked/cpp/language/function-try-block" title="Recent changes in pages linked from this page [k]" accesskey="k">Related changes</a></li><li id="t-upload"><a href="http://upload.cppreference.com/w/Special:Upload" title="Upload files [u]" accesskey="u">Upload file</a></li><li id="t-specialpages"><a href="http://en.cppreference.com/w/Special:SpecialPages" title="A list of all special pages [q]" accesskey="q">Special pages</a></li><li id="t-print"><a href="http://en.cppreference.com/mwiki/index.php?title=cpp/language/function-try-block&printable=yes" rel="alternate" title="Printable version of this page [p]" accesskey="p">Printable version</a></li><li id="t-permalink"><a href="http://en.cppreference.com/mwiki/index.php?title=cpp/language/function-try-block&oldid=69262" title="Permanent link to this revision of the page">Permanent link</a></li><li id="t-info"><a href="http://en.cppreference.com/mwiki/index.php?title=cpp/language/function-try-block&action=info">Page information</a></li> </ul>
</div>
<ul id="footer-info">
<li id="footer-info-lastmod"> This page was last modified on 1 April 2014, at 13:09.</li>
<li id="footer-info-viewcount">This page has been accessed 5,102 times.</li>
</ul>
<ul id="footer-places">
<li id="footer-places-privacy"><a href="http://en.cppreference.com/w/Cppreference:Privacy_policy" title="Cppreference:Privacy policy">Privacy policy</a></li>
<li id="footer-places-about"><a href="http://en.cppreference.com/w/Cppreference:About" title="Cppreference:About">About cppreference.com</a></li>
<li id="footer-places-disclaimer"><a href="http://en.cppreference.com/w/Cppreference:General_disclaimer" title="Cppreference:General disclaimer">Disclaimers</a></li>
</ul>
<ul id="footer-icons" class="noprint">
<li id="footer-poweredbyico">
<a href="http://www.mediawiki.org/"><img src="../../../mwiki/skins/common/images/poweredby_mediawiki_88x31.png" alt="Powered by MediaWiki" width="88" height="31" /></a> <a href="http://qbnz.com/highlighter/"><img src="../../../../upload.cppreference.com/mwiki/images/2/2b/powered_by_geshi_88x31.png" alt="Powered by GeSHi" height="31" width="88" /></a> <a href="http://www.tigertech.net/referral/cppreference.com"><img src="../../../../upload.cppreference.com/mwiki/images/9/94/powered_by_tigertech_88x31.png" alt="Hosted by Tiger Technologies" height="31" width="88" /></a> </li>
</ul>
<div style="clear:both">
</div>
</div>
</div>
<!-- /footer -->
<script>if(window.mw){
mw.loader.state({"site":"loading","user":"missing","user.groups":"ready"});
}</script>
<script src="../../../mwiki/load.php%3Fdebug=false&lang=en&modules=skins.cppreference2&only=scripts&skin=cppreference2&*"></script>
<script>if(window.mw){
mw.loader.load(["mediawiki.action.view.postEdit","mediawiki.user","mediawiki.page.ready","mediawiki.searchSuggest","mediawiki.hidpi","ext.gadget.ColiruCompiler"], null, true);
}</script>
<script src="../../../mwiki/load.php%3Fdebug=false&lang=en&modules=site&only=scripts&skin=cppreference2&*"></script>
<script type="text/javascript">
var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");
document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E"));
</script>
<script type="text/javascript">
var _gaq = _gaq || [];
_gaq.push(['_setAccount', 'UA-2828341-1']);
_gaq.push(['_setDomainName', 'cppreference.com']);
_gaq.push(['_trackPageview']);
</script><!-- Served in 0.961 secs. -->
</body>
<!-- Cached 20150313165906 -->
</html>
|
