__vic/doc/en/throw_errno.h.xml

<chapter xml:id="throw_errno.h">
<title><tt>__vic/throw_errno.h</tt></title>

<chapter xml:id="throw_errno">
<title><tt>throw_errno()</tt></title>

<code-block lang="C++"><![CDATA[
[[noreturn]] void throw_errno(const char *prompt);
[[noreturn]] void throw_errno(const char *prompt, int err_no);
]]></code-block>

<p>Throw an exception with global <tt>errno</tt> value or given
<tt>err_no</tt> correspondingly. Default exception type is
<xref to="libc_error"/> at the moment but can be changed at link time
by overriding this functions. For example <tt>std::system_error</tt> can be
used. Just create cpp-file with the following content in your project:</p>

<code-block lang="C++"><![CDATA[
#include<__vic/throw_errno.h>
#include<system_error>

//----------------------------------------------------------------------------
// Override library functions to throw std::system_error
//----------------------------------------------------------------------------
void __vic::throw_errno(const char *prompt, int err_no)
{
    throw std::system_error(err_no, std::system_category(), prompt);
}
//----------------------------------------------------------------------------
]]></code-block>

<p>It's enough to override only one functions because the second one just calls
<tt>throw_errno(prompt, errno)</tt>.</p>

<section><title>Example</title>
<code-block lang="C++"><![CDATA[
ssize_t written = ::write(fd, buf, buf_size);
if(written < 0) __vic::throw_errno("write");
// ...
]]></code-block>
</section>

</chapter>

</chapter>