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baae3a392a
Refactor API macros into a new header, boost/system/api_config.hpp. Prohibit user definition of API macros. Rationale: ensure all translation units use same definitions, cut number of environments that need to be tested. [SVN r62313]
852 lines
38 KiB
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852 lines
38 KiB
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<font size="7">System Library</font>
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<table border="0" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" bgcolor="#D7EEFF" width="100%">
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<i><b>Contents</b></i></td>
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<tr>
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<td width="100%" bgcolor="#E8F5FF">
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<a href="#Introduction">Introduction</a><br>
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<a href="#Macros">Macros</a><br>
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<a href="#Deprecated-names">Deprecated names</a><br>
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<a href="#Breaking-changes">Breaking changes</a><br>
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<a href="#Header-error_code">Header <boost/system/error_code.hpp></a><br>
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<a href="#Class-error_category">Class <code>error_category</code></a><br>
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<a href="#Class-error_category-synopsis">Class <code>error_category</code> synopsis</a><br>
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<a href="#Class-error_category-virtual-members">Class <code>error_category</code> virtual members</a><br>
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<a href="#Class-error_category-non-virtual-members">Class <code>error_category</code> non-virtual members</a><br>
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<a href="#Class-error_category-non-member-functions">Class <code>error_category</code>
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non-member functions</a><br>
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<a href="#Class-error_category-predefined-objects">Class <code>error_category</code> predefined objects</a><br>
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<a href="#Class-error_code">Class <code>error_code</code></a><br>
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<a href="#Class-error_code-synopsis">Class <code>error_code</code> synopsis</a><br>
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<a href="#Class-error_code-constructors">Class <code>error_code</code> constructors</a><br>
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<a href="#Class-error_code-modifiers">Class <code>error_code</code> modifiers</a><br>
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<a href="#Class-error_code-observers">Class <code>error_code</code> observers</a><br>
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<a href="#Class-error_condition">Class <code>error_condition</code></a><br>
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<a href="#Class-error_condition-synopsis">Class <code>error_condition</code> synopsis</a><br>
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<a href="#Class-error_condition-constructors">Class <code>error_condition</code> constructors</a><br>
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<a href="#Class-error_condition-modifiers">Class <code>error_condition</code> modifiers</a><br>
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<a href="#Class-error_condition-observers">Class <code>error_condition</code> observers</a><br>
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<a href="#throws-object"><code>throws</code> object</a><br>
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<a href="#Semantics-of-throws">Semantics of <code>throws</code> object</a><br>
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<a href="#Non-member-functions">Non-member functions</a><br>
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<a href="#Header-system_error">Header <boost/system/system_error.hpp></a><br>
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<a href="#Class-system_error">Class <code>system_error</code></a><br>
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</td>
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</tr>
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</table>
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<h2><a name="Introduction">Introduction</a></h2>
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<p>This reference documentation describes components that
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programs may use to report error conditions originating from the operating
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system or other low-level application program interfaces.</p>
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<p>Boost.System library components never change the value of <code>
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errno</code>.</p>
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<h2><a name="Macros">Macros</a></h2>
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<p>Users may defined the following macros if desired. Sensible defaults are
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provided, so users may ignore these macros if they prefer.</p>
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<table border="1" cellpadding="5" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" height="368">
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<tr>
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<td height="16"><b><i>Macro Name</i></b></td>
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<td height="16"><b><i>Default</i></b></td>
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<td height="16"><b><i>Effect if defined</i></b></td>
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</tr>
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<tr>
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<td valign="top" height="64"><code>BOOST_SYSTEM_DYN_LINK</code></td>
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<td valign="top" height="64">Defined if <code>BOOST_ALL_DYN_LINK</code> is defined,
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otherwise not defined.</td>
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<td valign="top" height="64">Boost.System library is dynamically linked. If not defined,
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static linking is assumed.</td>
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</tr>
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<tr>
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<td valign="top" height="47"><code>BOOST_SYSTEM_NO_LIB</code></td>
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<td valign="top" height="47">Defined if <code>BOOST_ALL_NO_LIB</code> is defined,
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otherwise not defined.</td>
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<td valign="top" height="47">Boost.System library does not use the Boost auto-link
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facility.</td>
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</tr>
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<tr>
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<td valign="top" height="32"><code>BOOST_SYSTEM_NO_DEPRECATED</code></td>
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<td valign="top" height="32">Not defined.</td>
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<td valign="top" height="32">Deprecated features are excluded.</td>
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</tr>
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</table>
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<h2><a name="Deprecated-names">Deprecated names</a></h2>
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<p>In the process of adding Boost.System to C++0x standard library, the C++
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committee changed some
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names. To ease transition, Boost.System deprecates the old
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names, but continues to provide them unless macro <code>BOOST_SYSTEM_NO_DEPRECATED</code>
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is defined.</p>
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<table border="1" cellpadding="5" cellspacing="1" style="border-collapse: collapse" bordercolor="#111111">
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<tr>
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<td><b><i>Old usage, now deprecated</i></b></td>
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<td><b><i>Replacement</i></b></td>
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</tr>
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<tr>
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<td><code>get_generic_category()</code></td>
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<td><code>generic_category()</code></td>
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</tr>
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<tr>
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<td><code>get_system_category()</code></td>
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<td><code>system_category()</code></td>
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</tr>
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<tr>
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<td><code>namespace posix</code></td>
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<td><code>namespace errc</code></td>
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</tr>
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<tr>
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<td><code>namespace posix_error</code></td>
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<td><code>namespace errc</code></td>
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</tr>
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<tr>
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<td><code>enum posix_errno</code></td>
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<td><code>enum errc_t</code></td>
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</tr>
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<tr>
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<td><code>get_posix_category()</code></td>
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<td><code>generic_category()</code></td>
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</tr>
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<tr>
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<td><code>posix_category</code></td>
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<td><code>generic_category()</code></td>
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</tr>
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<tr>
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<td><code>errno_ecat</code></td>
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<td><code>generic_category()</code></td>
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</tr>
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<tr>
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<td><code>native_ecat</code></td>
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<td><code>system_category()</code></td>
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</tr>
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</table>
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<h2><a name="Breaking-changes">Breaking changes</a></h2>
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<p>Two static consts are replaced by functions. These are breaking changes best
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fixed by globally adding () to these names to turn them into function calls.</p>
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<table border="1" cellpadding="5" cellspacing="1" style="border-collapse: collapse" bordercolor="#111111">
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<tr>
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<td><b><i>Old usage, now broken</i></b></td>
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<td><b><i>Replacement</i></b></td>
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</tr>
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<tr>
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<td><code>generic_category</code></td>
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<td><code>generic_category()</code></td>
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</tr>
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<tr>
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<td><code>system_category</code></td>
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<td><code>system_category()</code></td>
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</tr>
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</table>
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<p>User-defined BOOST_POSIX_API and BOOST_WINDOWS_API are no longer supported.</p>
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<h2><a name="Header-error_code">Header <boost/system/error_code.hpp></a></h2>
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<h3><boost/system/error_code.hpp> synopsis</h3>
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<blockquote>
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<pre>namespace boost
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{
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namespace system
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{
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class <a href="#Class-error_category">error_category</a>;
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class <a href="#Class-error_code">error_code</a>;
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class <a href="#Class-error_condition">error_condition</a>;
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// "Concept" helpers
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template< class T="" >
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struct is_error_code_enum { static const bool value = false; };
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template< class T="" >
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struct is_error_condition_enum { static const bool value = false; };
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// generic error_conditions
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namespace errc
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{
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enum errc_t
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{
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success = 0,
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address_family_not_supported, //EAFNOSUPPORT
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address_in_use, //EADDRINUSE
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address_not_available, //EADDRNOTAVAIL
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already_connected, //EISCONN
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argument_list_too_long, //E2BIG
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argument_out_of_domain, //EDOM
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bad_address, //EFAULT
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bad_file_descriptor, //EBADF
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bad_message, //EBADMSG
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broken_pipe, //EPIPE
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connection_aborted, //ECONNABORTED
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connection_already_in_progress, //EALREADY
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connection_refused, //ECONNREFUSED
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connection_reset, //ECONNRESET
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cross_device_link, //EXDEV
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destination_address_required, //EDESTADDRREQ
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device_or_resource_busy, //EBUSY
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directory_not_empty, //ENOTEMPTY
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executable_format_error, //ENOEXEC
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file_exists, //EEXIST
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file_too_large, //EFBIG
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filename_too_long, //ENAMETOOLONG
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function_not_supported, //ENOSYS
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host_unreachable, //EHOSTUNREACH
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identifier_removed, //EIDRM
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illegal_byte_sequence, //EILSEQ
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inappropriate_io_control_operation,//ENOTTY
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interrupted, //EINTR
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invalid_argument, //EINVAL
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invalid_seek, //ESPIPE
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io_error, //EIO
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is_a_directory, //EISDIR
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message_size, //EMSGSIZE
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network_down, //ENETDOWN
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network_reset, //ENETRESET
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network_unreachable, //ENETUNREACH
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no_buffer_space, //ENOBUFS
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no_child_process, //ECHILD
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no_link, //ENOLINK
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no_lock_available, //ENOLCK
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no_message_available, //ENODATA
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no_message, //ENOMSG
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no_protocol_option, //ENOPROTOOPT
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no_space_on_device, //ENOSPC
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no_stream_resources, //ENOSR
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no_such_device_or_address, //ENXIO
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no_such_device, //ENODEV
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no_such_file_or_directory, //ENOENT
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no_such_process, //ESRCH
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not_a_directory, //ENOTDIR
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not_a_socket, //ENOTSOCK
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not_a_stream, //ENOSTR
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not_connected, //ENOTCONN
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not_enough_memory, //ENOMEM
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not_supported, //ENOTSUP
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operation_canceled, //ECANCELED
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operation_in_progress, //EINPROGRESS
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operation_not_permitted, //EPERM
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operation_not_supported, //EOPNOTSUPP
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operation_would_block, //EWOULDBLOCK
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owner_dead, //EOWNERDEAD
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permission_denied, //EACCES
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protocol_error, //EPROTO
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protocol_not_supported, //EPROTONOSUPPORT
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read_only_file_system, //EROFS
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resource_deadlock_would_occur, //EDEADLK
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resource_unavailable_try_again, //EAGAIN
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result_out_of_range, //ERANGE
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state_not_recoverable, //ENOTRECOVERABLE
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stream_timeout, //ETIME
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text_file_busy, //ETXTBSY
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timed_out, //ETIMEDOUT
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too_many_files_open_in_system, //ENFILE
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too_many_files_open, //EMFILE
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too_many_links, //EMLINK
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too_many_synbolic_link_levels, //ELOOP
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value_too_large, //EOVERFLOW
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wrong_protocol_type //EPROTOTYPE
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};
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} // namespace errc
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template<> struct is_error_condition_enum<posix::posix_errno><errc::errc_t>
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{ static const bool value = true; };
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// <a href="#Non-member-functions">non-member functions</a>
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bool operator==( const error_code & lhs, const error_code & rhs );
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bool operator==( const error_code & code, const error_condition & condition );
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bool operator==( const error_condition & condition, const error_code & code );
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bool operator==( const error_condition & lhs, const error_condition & rhs );
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bool operator!=( const error_code & lhs, const error_code & rhs );
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bool operator!=( const error_code & code, const error_condition & condition );
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bool operator!=( const error_condition & condition, const error_code & code );
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bool operator!=( const error_condition & lhs, const error_condition & rhs );
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bool operator<( const error_code & lhs, const error_code & rhs );
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bool operator<( const error_condition & lhs, const error_condition & rhs );
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error_code make_error_code( errc::errc_t e );
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error_condition make_error_condition( errc::errc_t e );
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template <class charT, class traits>
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std::basic_ostream<charT,traits>&
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operator<<( basic_ostream<charT,traits>& os, const error_code & ec );
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size_t hash_value( const error_code & ec );
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}
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}</pre>
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</blockquote>
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<p>The value of each<code> errc_t</code> constant shall be the same as the
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value of the <code><cerrno></code> macro shown in the above synopsis.</p>
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<p>Users may specialize <code>is_error_code_enum</code> and <code>
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is_error_condition_enum</code> templates to indicate that a type is eligible for
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class <code>error_code</code> and <code>error_condition</code> automatic
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conversions respectively.</p>
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<h2><a name="Class-error_category">Class <code>error_category</code></a></h2>
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<p>The class <code>error_category</code> defines the base class for types used
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to identify the source and encoding of a particular category of error code.</p>
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<p><i>[Note:</i> Classes may be derived from <code>error_category</code>
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to support additional categories of errors. <i>--end note]</i></p>
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<p>The class <code>error_category</code> serves as a base class for types used
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to identify the source and encoding of a particular category of error code.
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Classes may be derived from <code>error_category</code> to support categories of
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errors in addition to those defined in the Boost System library. Such classes
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shall behave as specified in this subclause. [<i> Note:</i> <code>error_category</code>
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objects are passed by reference, and two such objects are equal if they have the
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same address. This means that applications using custom <code>error_category</code>
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types should create a single object of each such type. <i><EFBFBD>end note</i> ]</p>
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<h3><a name="Class-error_category-synopsis">Class <code>error_category</code> synopsis</a></h3>
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<blockquote>
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<pre>namespace boost
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{
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namespace system
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{
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class error_category : public noncopyable
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{
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public:
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virtual ~error_category();
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virtual const char * name() const = 0;
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virtual string message( int ev ) const = 0;
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virtual error_condition default_error_condition( int ev ) const;
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virtual bool equivalent( int code, const error_condition & condition ) const;
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virtual bool equivalent( const error_code & code, int condition ) const;
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bool operator==( const error_category & rhs ) const;
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bool operator!=( const error_category & rhs ) const;
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bool operator< ( const error_category & rhs ) const;
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};
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const error_category & system_category();
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const error_category & generic_category();
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}
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}</pre>
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</blockquote>
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<h3><a name="Class-error_category-virtual-members">Class <code>error_category</code> virtual members</a></h3>
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<p>Classes derived from <code>error_category</code> shall behave as specified in
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this subclause.</p>
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<pre>virtual const char * name() const=0;</pre>
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<blockquote>
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<p><i>Returns: </i>a string naming the error category.</p>
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<p><i>Throws:</i> Nothing.</p>
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</blockquote>
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<pre>virtual string message( int ev ) const=0;</pre>
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<blockquote>
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<p><i>Returns:</i> A string that describes the error denoted by
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<code>ev</code>.</p>
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<p><i>Throws:</i> Nothing.</p>
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</blockquote>
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<p><code>virtual error_condition default_error_condition( int ev ) const;</code></p>
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<blockquote>
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<p><i>Returns:</i> <code>error_condition( ev, *this )</code>.</p>
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<blockquote>
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<p> [<i>--Note:</i> Derived classes will typically convert <code>ev</code>
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to some portable <code>error_category</code>, such as <code>generic_category</code>,
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and return it as an <code>error_condition</code> for that category. <i>--end
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||
note</i>]</p>
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</blockquote>
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<p><i>Throws:</i> Nothing.</p>
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</blockquote>
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<p><code>virtual bool equivalent( int code, const error_condition &
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condition )
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const;</code></p>
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<blockquote>
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<p><i>Returns:</i> <code>default_error_condition( code ) == condition</code>.</p>
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<p><i>Throws:</i> Nothing.</p>
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</blockquote>
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<p><code>virtual bool equivalent( const error_code & code, int condition ) const;</code></p>
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<blockquote>
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<p><i>Returns:</i> <code>*this == code.category() && code.value() == condition</code>.</p>
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<p><i>Throws:</i> Nothing.</p>
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</blockquote>
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<h3><a name="Class-error_category-non-virtual-members">Class <code>error_category</code> non-virtual members</a></h3>
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<p><code>bool operator==( const error_category & rhs ) const;</code></p>
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<blockquote>
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<p><i>Returns:</i> <code>this == &rhs</code>.</p>
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</blockquote>
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<p><code>bool operator!=( const error_category & rhs ) const;</code></p>
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<blockquote>
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<p><i>Returns:</i> <code>this != &rhs</code>.</p>
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</blockquote>
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<pre>bool operator<( const error_category & rhs ) const;</pre>
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<blockquote>
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<p><i>Returns:</i> <code>std::less<const error_category*>()( this, &rhs )</code>.</p>
|
||
<blockquote>
|
||
<p><i>[Note:</i> <code>std::less</code> provides a total ordering for
|
||
pointers. <i>--end note]</i></p>
|
||
</blockquote>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<h3><a name="Class-error_category-non-member-functions">Class <code>error_category</code>
|
||
non-member functions</a></h3>
|
||
<pre>const error_category & system_category();</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> A reference to a <code>error_category</code> object
|
||
identifying errors originating from the operating system.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<pre>const error_category & generic_category();</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> A reference to a <code>error_category</code> object
|
||
identifying portable error conditions.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<h3><a name="Class-error_category-predefined-objects">Class <code>error_category</code>
|
||
predefined objects</a></h3>
|
||
<p>Predefined objects <code>system_category</code>
|
||
and <code>generic_category</code> identify system specific error codes and portable error conditions, respectively.</p>
|
||
<h2><a name="Class-error_code">Class <code>
|
||
error_code</code></a></h2>
|
||
<p>The class <code>error_code</code> describes an object used to hold error code
|
||
values, such as those originating from the operating<br>
|
||
system or other low-level application program interfaces. <i>[ Note: </i>Class
|
||
<code>error_code</code> is an adjunct to error reporting by<br>
|
||
exception. <i><EFBFBD>end note ]</i></p>
|
||
<h3><a name="Class-error_code-synopsis">Class <code>
|
||
error_code</code> synopsis</a></h3>
|
||
<blockquote>
|
||
<pre>namespace boost
|
||
{
|
||
namespace system
|
||
{
|
||
class error_code {
|
||
public:
|
||
|
||
// constructors:
|
||
error_code();
|
||
error_code( val, const error_category & cat );
|
||
template <class <code>ErrorCodeEnum</code>>
|
||
error_code(<code> ErrorCodeEnum</code> e,
|
||
typename enable_if<is_error_code_enum<<code>ErrorCodeEnum</code>> >::type* = 0);
|
||
|
||
// modifiers:
|
||
void assign( int val, const error_category & cat );
|
||
template<typename <code>ErrorCodeEnum</code>>
|
||
typename enable_if<is_error_code_enum<<code>ErrorCodeEnum</code>>, error_code>::type &
|
||
operator=( <code>ErrorCodeEnum</code> val );;
|
||
void clear();
|
||
|
||
// observers:
|
||
int value() const;
|
||
cont error_category & category() const;
|
||
error_condition default_error_condition() const;
|
||
string message() const;
|
||
operator unspecified-bool-type() const;
|
||
|
||
private:
|
||
int val_; // <i>exposition only</i>
|
||
const error_category * cat_; // <i>exposition only</i>
|
||
};
|
||
}
|
||
}</pre>
|
||
</blockquote>
|
||
<h3><a name="Class-error_code-constructors">Class <code>
|
||
error_code</code> constructors</a></h3>
|
||
<pre>error_code();</pre>
|
||
<blockquote>
|
||
<p><i>Effects: </i>Constructs an object of type <code>error_code</code>.</p>
|
||
<p><i>Postconditions:</i> <code>val_ == 0 && cat_ == &system_category</code>.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<pre>error_code( int val, const error_category & cat );</pre>
|
||
<blockquote>
|
||
<p><i>Effects: </i>Constructs an object of type <code>error_code</code>.</p>
|
||
<p><i>Postconditions:</i> <code>val_ == val && cat_ == &cat</code>.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<pre>template <class <code>ErrorCodeEnum</code>>
|
||
error_code(<code> errorCodeEnum</code> val,
|
||
typename enable_if<is_error_code_enum<<code>ErrorCodeEnum</code>> >::type* = 0);</pre>
|
||
<blockquote>
|
||
<p><i>Effects: </i>Constructs an object of type <code>error_code</code>.</p>
|
||
<p><i>Postconditions:</i> <code>*this == make_error_code( val )</code>.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<h3><a name="Class-error_code-modifiers">Class <code>
|
||
error_code</code> modifiers</a></h3>
|
||
<pre>void assign( int val, const error_category & cat );</pre>
|
||
<blockquote>
|
||
<p><i>Postconditions:</i> <code>val_ == val && cat_ == &cat</code>.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<pre>template<typename <code>ErrorCodeEnum</code>>
|
||
typename enable_if<is_error_code_enum<<code>ErrorCodeEnum</code>>, error_code>::type &
|
||
operator=( <code>ErrorCodeEnum</code> val );</pre>
|
||
<blockquote>
|
||
<p><i>Postconditions:</i> <code>*this == make_error_code( val )</code>.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<p><code>void clear();</code></p>
|
||
<blockquote>
|
||
<p><i>postcondition:</i> <code>value() == 0 && category() == generic_category</code></p>
|
||
</blockquote>
|
||
<h3><a name="Class-error_code-observers">Class <code>
|
||
error_code</code> observers</a></h3>
|
||
<p><code>int value() const;</code></p>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>val_</code>.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<p><code>const error_category & category() const;</code></p>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>*cat_</code>.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<pre>error_condition default_error_condition() const;</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>category().default_error_condition( value())</code>.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<p><code>string message() const;</code></p>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>category().message( value())</code>.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<p><code>operator <i>unspecified-bool-type</i>() const;</code></p>
|
||
<blockquote>
|
||
<p><i>Returns:</i> if <code>value() != 0</code>, returns a value that will evaluate
|
||
<code>true</code> in a boolean context; otherwise, returns a value that will
|
||
evaluate <code>false</code> in a boolean context. The value type returned shall
|
||
not be convertible to <code>int</code>.</p>
|
||
<p><i>Throws:</i> nothing.</p>
|
||
<p><i>[Note: </i>This conversion can be used in contexts where a <code>bool</code>
|
||
is expected ( e.g., an <code>if</code> condition ); however, implicit conversions
|
||
( e.g., to <code>int</code>) that can occur with <code>bool</code> are not
|
||
allowed, eliminating some sources of user error. One possible implementation
|
||
choice for this type is pointer-to-member. <i>--end note ]</i></p>
|
||
</blockquote>
|
||
<h2><a name="Class-error_condition">Class <code>error_condition</code></a></h2>
|
||
<p>The class <code>error_condition</code> describes an object used to hold
|
||
values identifying error conditions. <i>[ Note: </i><code>error_condition</code>
|
||
values are portable abstractions, while <code>error_code</code> values are
|
||
implementation specific. <i>--end note ]</i></p>
|
||
<h3><a name="Class-error_condition-synopsis">Class <code>error_condition</code> synopsis</a></h3>
|
||
<blockquote>
|
||
<pre>namespace boost
|
||
{
|
||
namespace system
|
||
{
|
||
class error_condition
|
||
{
|
||
public:
|
||
|
||
// constructors:
|
||
error_condition();
|
||
error_condition( int val, const error_category & cat );
|
||
template <class ErrorConditionEnum>
|
||
error_condition( errorConditionEnum val,
|
||
typename enable_if<is_error_condition_enum<ErrorConditionEnum> >::type* = 0 );
|
||
|
||
// modifiers:
|
||
void assign( int val, const error_category & cat );
|
||
template<typename ErrorConditionEnum>
|
||
typename enable_if<is_error_condition_enum<ErrorConditionEnum>, error_code>::type &
|
||
operator=( ErrorConditionEnum val );
|
||
void clear();
|
||
|
||
// observers:
|
||
int value() const;
|
||
const error_category & category() const;
|
||
string message() const;
|
||
operator unspecified-bool-type () const;
|
||
|
||
private:
|
||
int val_; // <i>exposition only</i>
|
||
const error_category * cat_; // <i>exposition only</i>
|
||
};
|
||
}
|
||
}</pre>
|
||
</blockquote>
|
||
<h3><a name="Class-error_condition-constructors">Class <code>error_condition</code>
|
||
constructors</a></h3>
|
||
<pre>error_condition(); </pre>
|
||
<blockquote>
|
||
<p><i>Effects:</i> Constructs an object of type <code>error_condition</code>.</p>
|
||
<p><i>Postconditions:</i> <code>val_ == 0 and cat_ == &generic_category</code>.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<pre>error_condition( int val, const error_category & cat );</pre>
|
||
<blockquote>
|
||
<p><i>Effects: </i>Constructs an object of type error_condition.</p>
|
||
<p><i>Postconditions:</i> <code>val_ == val and cat_ == &cat</code>.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<pre>template <class ErrorConditionEnum>
|
||
error_condition( errorConditionEnum val,
|
||
typename enable_if<is_error_condition_enum<ErrorConditionEnum> >::type* = 0 );</pre>
|
||
<blockquote>
|
||
<p><i>Effects:</i> Constructs an object of type <code>error_condition</code>.</p>
|
||
<p><i>Postconditions:</i> <code>*this == make_error_condition( val )</code>.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<h3><a name="Class-error_condition-modifiers">Class <code>error_condition</code>
|
||
modifiers</a></h3>
|
||
<pre>void assign( int val, const error_category & cat ); </pre>
|
||
<blockquote>
|
||
<p><i>Postconditions:</i> <code>val_ == val and cat_ == &cat</code>. </p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<pre>template<typename ErrorConditionEnum>
|
||
typename enable_if<is_error_condition_enum<ErrorConditionEnum>, error_code>::type &
|
||
operator=( ErrorConditionEnum val );</pre>
|
||
<blockquote>
|
||
<p><i>Postconditions:</i> <code>*this == make_error_condition( val )</code>.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<p><code>void clear();</code></p>
|
||
<blockquote>
|
||
<p><i>postcondition:</i> <code>value() == 0 && category() == generic_category</code></p>
|
||
</blockquote>
|
||
<h3><a name="Class-error_condition-observers">Class <code>error_condition</code>
|
||
observers</a></h3>
|
||
<pre>int value() const;</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>val_</code>.</p>
|
||
<p><i>Throws:</i> Nothing</p>
|
||
</blockquote>
|
||
<pre>const error_category & category() const;</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>*cat_</code>.</p>
|
||
<p>Throws: Nothing.</p>
|
||
</blockquote>
|
||
<pre>string message() const;</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>category().message( value() )</code>.</p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
</blockquote>
|
||
<pre>operator unspecified-bool-type () const;</pre>
|
||
<blockquote>
|
||
<p><i>Returns: </i>If <code>value() != 0</code>, returns a value that will
|
||
evaluate <code>true</code> in a boolean context; otherwise, returns a value
|
||
that will evaluate <code>false</code>. The return type shall not be
|
||
convertible to <code>int</code>. </p>
|
||
<p><i>Throws:</i> Nothing.</p>
|
||
<p><i> [ Note:</i> This conversion can be used in contexts where a <code>bool</code>
|
||
is expected ( e.g., an if condition ); however, implicit conversions ( e.g., to
|
||
<code>int</code>) that can occur with <code>bool</code> are not allowed,
|
||
eliminating some sources of user error. One possible implementation choice for
|
||
this type is pointer to member. <i>--end note</i> <i>]</i></p>
|
||
</blockquote>
|
||
<h2><a name="throws-object"><code>throws</code> object</a></h2>
|
||
<pre>extern error_code throws;</pre>
|
||
<p>The predefined <code>error_code</code> object <code>throws</code> is supplied
|
||
for use as a "throw on error" tag.</p>
|
||
<h2><a name="Semantics-of-throws">Semantics of <code>throws</code></a> object</h2>
|
||
<p>Functions that specify an argument in the form <code>error_code& ec=throws</code>,
|
||
with appropriate namespace qualifiers, have the following error handling
|
||
semantics:</p>
|
||
<blockquote>
|
||
<p><i>Postconditions:</i></p>
|
||
<blockquote>
|
||
<p>If <code>&ec != &throws</code> and an error occurred:</p>
|
||
<ul>
|
||
<li> <code>ec.value()</code> returns the implementation specific error
|
||
number for the particular error that occurred.</li>
|
||
<li><code>ec.category()</code> returns the <code>
|
||
<a href="#Class-error_category">error_category</a></code> for <code>ec.value()</code>.</li>
|
||
</ul>
|
||
<p>if <code>&ec != &throws</code> and an error did not occur, <code>ec.clear()</code>.</p>
|
||
</blockquote>
|
||
<p><i>Throws:</i></p>
|
||
<blockquote>
|
||
<p>If an error occurs and <code>&ec == &throws</code>, throws an exception of type
|
||
<code><a href="#Class-system_error">system_error</a></code> or of a type
|
||
derived from <code><a href="#Class-system_error">system_error</a></code>. The
|
||
exception's <code>code()</code> member function returns a reference to an
|
||
<code>error_code</code> object with the behavior specified in <i>
|
||
Postconditions</i>.</p>
|
||
</blockquote>
|
||
</blockquote>
|
||
<h2><a name="Non-member-functions">Non-member functions</a></h2>
|
||
<pre>bool operator==( const error_code & lhs, const error_code & rhs );</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>lhs.category() == rhs.category() && lhs.value() ==
|
||
rhs.value()</code>.</p>
|
||
<p><i>Throws: </i>Nothing.</p>
|
||
</blockquote>
|
||
<pre>bool operator==( const error_code & code, const error_condition & condition );
|
||
bool operator==( const error_condition & condition, const error_code & code );</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>code.category().equivalent( code.value(), condition )<br>
|
||
|| condition.category().equivalent( code, condition.value() )</code>.</p>
|
||
<p><i>Throws: </i>Nothing.</p>
|
||
</blockquote>
|
||
<pre>bool operator==( const error_condition & lhs, const error_condition & rhs );</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>lhs.category() == rhs.category() && lhs.value() ==
|
||
rhs.value()</code>.</p>
|
||
<p><i>Throws: </i>Nothing.</p>
|
||
</blockquote>
|
||
<pre>bool operator!=( const error_code & lhs, const error_code & rhs );</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>!(lhs == rhs )</code>.</p>
|
||
<p><i>Throws: </i>Nothing.</p>
|
||
</blockquote>
|
||
<pre>bool operator!=( const error_code & code, const error_condition & condition );
|
||
bool operator!=( const error_condition & condition, const error_code & code );</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i><code> !( code == condition )</code>.</p>
|
||
<p><i>Throws: </i>Nothing.</p>
|
||
</blockquote>
|
||
<pre>bool operator!=( const error_condition & lhs, const error_condition & rhs );</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>!(lhs == rhs )</code>.</p>
|
||
<p><i>Throws: </i>Nothing.</p>
|
||
</blockquote>
|
||
<pre>bool operator<( const error_code & lhs, const error_code & rhs );</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>lhs.category() < rhs.category()<br>
|
||
|| (lhs.category() == rhs.category() && lhs.value() < rhs.value())</code>.</p>
|
||
<p><i>Throws: </i>Nothing.</p>
|
||
</blockquote>
|
||
<pre>bool operator<( const error_condition & lhs, const error_condition & rhs );</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>lhs.category() < rhs.category()<br>
|
||
|| (lhs.category() == rhs.category() && lhs.value() < rhs.value())</code>.</p>
|
||
<p><i>Throws: </i>Nothing.</p>
|
||
</blockquote>
|
||
<pre>error_code make_error_code( errc::errc_t e );</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>error_code( e, generic_category)</code>.</p>
|
||
</blockquote>
|
||
<pre>error_condition make_error_condition( errc::errc_t e );</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>error_condition( static_cast<int>( e ), generic_category)</code>.</p>
|
||
</blockquote>
|
||
|
||
<pre>template <class charT, class traits>
|
||
std::basic_ostream<charT,traits>&
|
||
operator<<( basic_ostream<charT,traits>& os, const error_code & ec );</pre>
|
||
<blockquote>
|
||
<p><i>Effects:</i> <code>os << ec.category().name() << ':' << ec.value()</code>.</p>
|
||
<p><i>Returns:</i> <code>os</code>.</p>
|
||
</blockquote>
|
||
<pre>size_t <a name="hash_value">hash_value</a>( const error_code & ec );</pre>
|
||
<blockquote>
|
||
<p><i>Returns: </i> A hash value representing <code>ec</code>.</p>
|
||
</blockquote>
|
||
|
||
<h2><a name="Header-system_error">Header <boost/system/system_error.hpp></a></h2>
|
||
|
||
<h3><a name="Class-system_error">Class <code>
|
||
system_error</code></a></h3>
|
||
<p>The class <code>system_error</code> describes an exception object used to
|
||
report errors that have an associated <code><a href="#Class-error_code">error_code</a></code>. Such errors typically originate from operating system or other low-level
|
||
application program interfaces.</p>
|
||
<blockquote>
|
||
<pre>namespace boost
|
||
{
|
||
namespace system
|
||
{
|
||
class system_error : public std::runtime_error
|
||
{
|
||
public:
|
||
system_error( error_code ec );
|
||
system_error( error_code ec, const char * what_arg );
|
||
system_error( error_code ec, const std::string & what_arg );
|
||
system_error( int ev, const error_category & ecat,
|
||
const char * what_arg );
|
||
system_error( int ev, const error_category & ecat,
|
||
const std::string & what_arg );
|
||
system_error( int ev, const error_category & ecat);
|
||
|
||
const error_code & code() const throw();
|
||
const char * what() const throw();
|
||
};
|
||
}
|
||
}</pre>
|
||
</blockquote>
|
||
<pre>system_error( error_code ec );</pre>
|
||
<blockquote>
|
||
<p><i>Effects:</i> Constructs an object of class <code>system_error</code>.</p>
|
||
<p><i>Postcondition:</i> <code>code() == ec <br>
|
||
&& std::strcmp( this->runtime_error::what(), "" ) == 0</code></p>
|
||
</blockquote>
|
||
<pre>system_error( error_code ec, const char * what_arg );</pre>
|
||
<blockquote>
|
||
<p><i>Effects:</i> Constructs an object of class <code>system_error</code>.</p>
|
||
<p><i>Postcondition:</i> <code>code() == ec <br>
|
||
&& std::strcmp( this->runtime_error::what(), what_arg ) == 0</code></p>
|
||
</blockquote>
|
||
<pre>system_error( error_code ec, const std::string & what_arg );</pre>
|
||
<blockquote>
|
||
<p><i>Effects:</i> Constructs an object of class <code>system_error</code>.</p>
|
||
<p><i>Postcondition:</i> <code>code() == ec <br>
|
||
&& std::strcmp( this->runtime_error::what(), what_arg.c_str() ) == 0</code></p>
|
||
</blockquote>
|
||
<pre>system_error( int ev, const error_category & ecat,
|
||
const char * what_arg );</pre>
|
||
<blockquote>
|
||
<p><i>Effects:</i> Constructs an object of class <code>system_error</code>.</p>
|
||
<p><i>Postcondition:</i> <code>code() == error_code( ev, ecat )<br>
|
||
&& std::strcmp( this->runtime_error::what(), what_arg ) == 0</code></p>
|
||
</blockquote>
|
||
<pre>system_error( int ev, const error_category & ecat,
|
||
const std::string & what_arg );</pre>
|
||
<blockquote>
|
||
<p><i>Effects:</i> Constructs an object of class <code>system_error</code>.</p>
|
||
<p><i>Postcondition:</i> <code>code() == error_code( ev, ecat )<br>
|
||
&& std::strcmp( this->runtime_error::what(), what_arg.c_str() ) == 0</code></p>
|
||
</blockquote>
|
||
<pre>system_error( int ev, const error_category & ecat );</pre>
|
||
<blockquote>
|
||
<p><i>Effects:</i> Constructs an object of class <code>system_error</code>.</p>
|
||
<p><i>Postcondition:</i> <code>code() == error_code( ev, ecat )<br>
|
||
&& std::strcmp( this->runtime_error::what(), "" ) == 0</code></p>
|
||
</blockquote>
|
||
<pre>const error_code & code() const;</pre>
|
||
<blockquote>
|
||
<p><i>Returns:</i> <code>ec</code> or <code>error_code( ev, ecat )</code>, from
|
||
the constructor, as appropriate.</p>
|
||
</blockquote>
|
||
<pre>const char * what() const;</pre>
|
||
<blockquote>
|
||
<p><i>Returns: </i>A string incorporating <code>
|
||
this->runtime_error::what()</code> and <code>
|
||
code.message()</code>.</p>
|
||
</blockquote>
|
||
<hr>
|
||
|
||
<p>Revised
|
||
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%B %d, %Y" startspan -->May 29, 2010<!--webbot bot="Timestamp" endspan i-checksum="11273" --> </font>
|
||
</p>
|
||
|
||
<p><EFBFBD> Copyright Beman Dawes, 2006, 2007, 2008</p>
|
||
|
||
<p>Distributed under the Boost Software License, Version 1.0. See
|
||
<a href="http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a></p>
|
||
|
||
</body>
|
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