1 | <?xml version="1.0" encoding="utf-8" ?> |
---|
2 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> |
---|
3 | <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> |
---|
4 | <head> |
---|
5 | <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> |
---|
6 | <meta name="generator" content="Docutils 0.3.6: http://docutils.sourceforge.net/" /> |
---|
7 | <title>The MPL Reference Manual: BOOST_MPL_ASSERT_MSG</title> |
---|
8 | <link rel="stylesheet" href="../style.css" type="text/css" /> |
---|
9 | </head> |
---|
10 | <body class="docframe refmanual"> |
---|
11 | <table class="header"><tr class="header"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./assert.html" class="navigation-link">Prev</a> <a href="./assert-not.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./assert.html" class="navigation-link">Back</a> <a href="./assert-not.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./asserts.html" class="navigation-link">Up</a> <a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td> |
---|
12 | <td class="header-group page-location"><a href="../refmanual.html" class="navigation-link">Front Page</a> / <a href="./macros.html" class="navigation-link">Macros</a> / <a href="./asserts.html" class="navigation-link">Asserts</a> / <a href="./assert-msg.html" class="navigation-link">BOOST_MPL_ASSERT_MSG</a></td> |
---|
13 | </tr></table><div class="header-separator"></div> |
---|
14 | <div class="section" id="assert-msg"> |
---|
15 | <h1><a class="toc-backref" href="./asserts.html#id512" name="assert-msg">BOOST_MPL_ASSERT_MSG</a></h1> |
---|
16 | <div class="section" id="asserts-assert-synopsis"> |
---|
17 | <h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3> |
---|
18 | <pre class="literal-block"> |
---|
19 | #define <a href="./assert-msg.html" class="identifier">BOOST_MPL_ASSERT_MSG</a>( condition, message, types ) \ |
---|
20 | <em>unspecified token sequence</em> \ |
---|
21 | /**/ |
---|
22 | </pre> |
---|
23 | </div> |
---|
24 | <div class="section" id="asserts-assert-description"> |
---|
25 | <h3><a class="subsection-title" href="#description" name="description">Description</a></h3> |
---|
26 | <p>Generates a compilation error with an embedded custom message when the condition |
---|
27 | doesn't hold.</p> |
---|
28 | </div> |
---|
29 | <div class="section" id="asserts-assert-header"> |
---|
30 | <h3><a class="subsection-title" href="#header" name="header">Header</a></h3> |
---|
31 | <pre class="literal-block"> |
---|
32 | #include <<a href="../../../../boost/mpl/assert.hpp" class="header">boost/mpl/assert.hpp</a>> |
---|
33 | </pre> |
---|
34 | </div> |
---|
35 | <div class="section" id="asserts-assert-parameters"> |
---|
36 | <h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3> |
---|
37 | <table border="1" class="table"> |
---|
38 | <colgroup> |
---|
39 | <col width="15%" /> |
---|
40 | <col width="36%" /> |
---|
41 | <col width="48%" /> |
---|
42 | </colgroup> |
---|
43 | <thead valign="bottom"> |
---|
44 | <tr><th>Parameter</th> |
---|
45 | <th>Requirement</th> |
---|
46 | <th>Description</th> |
---|
47 | </tr> |
---|
48 | </thead> |
---|
49 | <tbody valign="top"> |
---|
50 | <tr><td><tt class="literal"><span class="pre">condition</span></tt></td> |
---|
51 | <td>An integral constant expression</td> |
---|
52 | <td>A condition to be asserted.</td> |
---|
53 | </tr> |
---|
54 | <tr><td><tt class="literal"><span class="pre">message</span></tt></td> |
---|
55 | <td>A legal identifier token</td> |
---|
56 | <td>A custom message in a form of a legal C++ |
---|
57 | identifier token.</td> |
---|
58 | </tr> |
---|
59 | <tr><td><tt class="literal"><span class="pre">types</span></tt></td> |
---|
60 | <td>A legal function parameter list</td> |
---|
61 | <td>A parenthized list of types to be displayed |
---|
62 | in the error message.</td> |
---|
63 | </tr> |
---|
64 | </tbody> |
---|
65 | </table> |
---|
66 | </div> |
---|
67 | <div class="section" id="asserts-assert-expression-semantics"> |
---|
68 | <h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> |
---|
69 | <p>For any integral constant expression <tt class="literal"><span class="pre">expr</span></tt>, legal C++ identifier <tt class="literal"><span class="pre">message</span></tt>, and |
---|
70 | arbitrary types <tt class="literal"><span class="pre">t1</span></tt>, <tt class="literal"><span class="pre">t2</span></tt>,... <tt class="literal"><span class="pre">tn</span></tt>:</p> |
---|
71 | <pre class="literal-block"> |
---|
72 | <a href="./assert-msg.html" class="identifier">BOOST_MPL_ASSERT_MSG</a>( expr, message, (t1, t2,... tn) ); |
---|
73 | </pre> |
---|
74 | <table class="field-list" frame="void" rules="none"> |
---|
75 | <col class="field-name" /> |
---|
76 | <col class="field-body" /> |
---|
77 | <tbody valign="top"> |
---|
78 | <tr class="field"><th class="field-name">Return type:</th><td class="field-body">None.</td> |
---|
79 | </tr> |
---|
80 | <tr class="field"><th class="field-name">Precondition:</th><td class="field-body"><tt class="literal"><span class="pre">t1</span></tt>, <tt class="literal"><span class="pre">t2</span></tt>,... <tt class="literal"><span class="pre">tn</span></tt> are non-<tt class="literal"><span class="pre">void</span></tt>.</td> |
---|
81 | </tr> |
---|
82 | <tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><p class="first">Generates a compilation error if <tt class="literal"><span class="pre">expr::value</span> <span class="pre">!=</span> <span class="pre">true</span></tt>, otherwise |
---|
83 | has no effect.</p> |
---|
84 | <p>When possible within the compiler's diagnostic capabilities, |
---|
85 | the error message will include the <tt class="literal"><span class="pre">message</span></tt> identifier and the parenthized |
---|
86 | list of <tt class="literal"><span class="pre">t1</span></tt>, <tt class="literal"><span class="pre">t2</span></tt>,... <tt class="literal"><span class="pre">tn</span></tt> types, and have a general form of:</p> |
---|
87 | <pre class="last literal-block"> |
---|
88 | <em>...</em> ************( <em>...</em>::message )************)(t1, t2,... tn) <em>...</em> |
---|
89 | </pre> |
---|
90 | </td> |
---|
91 | </tr> |
---|
92 | </tbody> |
---|
93 | </table> |
---|
94 | <pre class="literal-block"> |
---|
95 | <a href="./assert-msg.html" class="identifier">BOOST_MPL_ASSERT_MSG</a>( expr, message, (types<t1, t2,... tn>) ); |
---|
96 | </pre> |
---|
97 | <table class="field-list" frame="void" rules="none"> |
---|
98 | <col class="field-name" /> |
---|
99 | <col class="field-body" /> |
---|
100 | <tbody valign="top"> |
---|
101 | <tr class="field"><th class="field-name">Return type:</th><td class="field-body">None.</td> |
---|
102 | </tr> |
---|
103 | <tr class="field"><th class="field-name">Precondition:</th><td class="field-body">None.</td> |
---|
104 | </tr> |
---|
105 | <tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><p class="first">Generates a compilation error if <tt class="literal"><span class="pre">expr::value</span> <span class="pre">!=</span> <span class="pre">true</span></tt>, otherwise |
---|
106 | has no effect.</p> |
---|
107 | <p>When possible within the compiler's diagnostics capabilities, |
---|
108 | the error message will include the <tt class="literal"><span class="pre">message</span></tt> identifier and the list of |
---|
109 | <tt class="literal"><span class="pre">t1</span></tt>, <tt class="literal"><span class="pre">t2</span></tt>,... <tt class="literal"><span class="pre">tn</span></tt> types, and have a general form of:</p> |
---|
110 | <pre class="last literal-block"> |
---|
111 | <em>...</em> ************( <em>...</em>::message )************)(types<t1, t2,... tn>) <em>...</em> |
---|
112 | </pre> |
---|
113 | </td> |
---|
114 | </tr> |
---|
115 | </tbody> |
---|
116 | </table> |
---|
117 | </div> |
---|
118 | <div class="section" id="asserts-assert-example"> |
---|
119 | <h3><a class="subsection-title" href="#example" name="example">Example</a></h3> |
---|
120 | <pre class="literal-block"> |
---|
121 | template< typename T > struct my |
---|
122 | { |
---|
123 | // ... |
---|
124 | <a href="./assert-msg.html" class="identifier">BOOST_MPL_ASSERT_MSG</a>( |
---|
125 | is_integral<T>::value |
---|
126 | , NON_INTEGRAL_TYPES_ARE_NOT_ALLOWED |
---|
127 | , (T) |
---|
128 | ); |
---|
129 | }; |
---|
130 | |
---|
131 | my<void*> test; |
---|
132 | |
---|
133 | // In instantiation of `my<void*>': |
---|
134 | // instantiated from here |
---|
135 | // conversion from ` |
---|
136 | // mpl_::failed************(my<void*>:: |
---|
137 | // NON_INTEGRAL_TYPES_ARE_NOT_ALLOWED::************)(void*) |
---|
138 | // ' to non-scalar type `mpl_::assert<false>' requested |
---|
139 | </pre> |
---|
140 | </div> |
---|
141 | <div class="section" id="asserts-assert-see-also"> |
---|
142 | <h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> |
---|
143 | <p><a class="reference" href="./asserts.html">Asserts</a>, <a class="refentry reference" href="./assert.html"><tt class="refentry literal"><span class="pre">BOOST_MPL_ASSERT</span></tt></a>, <a class="refentry reference" href="./assert-not.html"><tt class="refentry literal"><span class="pre">BOOST_MPL_ASSERT_NOT</span></tt></a>, <a class="refentry reference" href="./assert-relation.html"><tt class="refentry literal"><span class="pre">BOOST_MPL_ASSERT_RELATION</span></tt></a></p> |
---|
144 | <!-- modtime: November 10, 2004 04:45:24 +0000 --> |
---|
145 | <!-- Macros/Asserts//BOOST_MPL_ASSERT_NOT --> |
---|
146 | </div> |
---|
147 | </div> |
---|
148 | |
---|
149 | <div class="footer-separator"></div> |
---|
150 | <table class="footer"><tr class="footer"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./assert.html" class="navigation-link">Prev</a> <a href="./assert-not.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./assert.html" class="navigation-link">Back</a> <a href="./assert-not.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./asserts.html" class="navigation-link">Up</a> <a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td> |
---|
151 | </tr></table></body> |
---|
152 | </html> |
---|