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4 | <TITLE>Class Template chain</TITLE> |
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8 | <BODY> |
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9 | |
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10 | <!-- Begin Banner --> |
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11 | |
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12 | <H1 CLASS="title">Class Template <CODE>char_traits</CODE></H1> |
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13 | <HR CLASS="banner"> |
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14 | |
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15 | <!-- End Banner --> |
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16 | |
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17 | <DL class="page-index"> |
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18 | <DT><A href="#description">Description</A></DT> |
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19 | <DT><A href="#headers">Headers</A></DT> |
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20 | <DT><A href="#reference">Reference</A></DT> |
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21 | </DL> |
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22 | |
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23 | <HR> |
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24 | |
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25 | <A NAME="description"></A> |
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26 | <H2>Description</H2> |
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27 | |
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28 | <P> |
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29 | The class template <CODE>boost::iostreams::char_traits</CODE> is a derived class of <CODE>std::char_traits</CODE> which has an additional static function <A HREF='#would_block'><CODE>would_block</CODE></A>, used to indicate that an attempt to read a character has failed because no input is currently available. |
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30 | </P> |
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31 | |
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32 | <P> |
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33 | The constants <CODE>WOULD_BLOCK</CODE> and <CODE>WWOULD_BLOCK</CODE> are provided for convenience. |
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34 | </P> |
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35 | |
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36 | <A NAME="headers"></A> |
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37 | <H2>Headers</H2> |
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38 | |
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39 | <DL class="page-index"> |
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40 | <DT><A CLASS="header" HREF="../../../../boost/iostreams/char_traits.hpp"><CODE><boost/iostreams/char_traits.hpp></CODE></A></DT> |
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41 | </DL> |
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42 | |
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43 | <A NAME="reference"></A> |
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44 | <H2>Reference</H2> |
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45 | |
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46 | <A NAME="synopsis"></A> |
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47 | <H3>Synopsis</H3> |
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48 | |
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49 | <PRE CLASS="broken_ie"><SPAN CLASS="keyword">namespace</SPAN> boost { <SPAN CLASS="keyword">namespace</SPAN> iostreams { |
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50 | |
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51 | <SPAN CLASS="keyword">const</SPAN> <SPAN CLASS="keyword">int</SPAN> <A CLASS="documented" HREF="#WOULD_BLOCK">WOULD_BLOCK</A>; |
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52 | |
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53 | <SPAN CLASS="keyword">const</SPAN> std::wint_t <A CLASS="documented" HREF="#WWOULD_BLOCK">WWOULD_BLOCK</A>; |
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54 | |
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55 | <SPAN CLASS="keyword">template</SPAN><<SPAN CLASS="keyword">typename</SPAN> <A CLASS="documented" HREF="#template_params">Ch</A>> |
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56 | <SPAN CLASS="keyword">class</SPAN> <A CLASS="documented" HREF="#template_params">char_traits</A> : public std::char_traits<Ch> { |
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57 | <SPAN CLASS='keyword'>static</SPAN> <SPAN CLASS='keyword'>typename</SPAN> std::char_traits<Ch>::int_type <A CLASS='documented' HREF='#would_block'>would_block</A>(); |
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58 | }; |
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59 | |
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60 | } } // End namespace boost::io</PRE> |
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61 | |
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62 | <A NAME="WOULD_BLOCK"></A> |
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63 | <H3>Constant <CODE>WOULD_BLOCK</CODE></H3> |
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64 | |
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65 | <PRE CLASS="broken_ie"> <SPAN CLASS="keyword">const</SPAN> <SPAN CLASS="keyword">int</SPAN> WOULD_BLOCK;</PRE> |
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66 | |
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67 | <P>The return value of <CODE>char_traits<char>::would_block</CODE>. Used by the function template <A HREF="../functions/get.html"><CODE>get</CODE></A> to indicate that no character could be returned because input was temporarily unavailable.</P> |
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68 | |
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69 | <A NAME="WWOULD_BLOCK"></A> |
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70 | <H3>Constant <CODE>WWOULD_BLOCK</CODE></H3> |
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71 | |
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72 | <PRE CLASS="broken_ie"> <SPAN CLASS="keyword">const</SPAN> std::wint_t WWOULD_BLOCK;</PRE> |
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73 | |
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74 | <P>The return value of <CODE>char_traits<wchar_t>::would_block</CODE>. Used by the function template <A HREF="../functions/get.html"><CODE>get</CODE></A> to indicate that no character could be returned because input was temporarily unavailable.</P> |
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75 | |
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76 | <A NAME="char_traits"></A> |
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77 | <H3>Class Template <CODE>boost::iostreams::char_traits</CODE></H3> |
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78 | |
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79 | <A NAME="template_params"></A> |
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80 | <H4>Template parameters</H4> |
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81 | |
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82 | <TABLE STYLE="margin-left:2em" BORDER=0 CELLPADDING=2> |
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83 | <TR> |
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84 | <TD VALIGN="top"><I>Ch</I></TD><TD WIDTH="2em" VALIGN="top">-</TD> |
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85 | <TD>The character type</TD> |
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86 | </TR> |
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87 | </TABLE> |
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88 | |
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89 | <A NAME="char_traits"></A> |
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90 | <H4><CODE>char_traits::would_block</CODE></H4> |
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91 | |
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92 | <PRE CLASS="broken_ie"> <SPAN CLASS='keyword'>static</SPAN> <SPAN CLASS='keyword'>typename</SPAN> std::char_traits<Ch>::int_type would_block();</PRE> |
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93 | |
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94 | <P> |
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95 | Returns an instance of <CODE>int_type</CODE> used by the function template <A HREF='../functions/get.html'><CODE>get</CODE></A> to indicate that an attempt to read a character from a <A HREF='../concepts/source.html'>Source</A> has failed because no input is currently available. Future attempts to read a character may succeed. |
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96 | </P> |
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97 | |
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98 | <!-- Begin Footer --> |
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99 | |
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100 | <HR> |
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101 | <P CLASS="copyright">Revised |
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102 | <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan --> |
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103 | 20 May, 2004 |
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104 | <!--webbot bot="Timestamp" endspan i-checksum="38504" --> |
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105 | </P> |
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106 | |
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107 | <P CLASS="copyright">© Copyright <A HREF="http://www.kangaroologic.com" TARGET="_top">Jonathan Turkanis</A>, 2004</P> |
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108 | <P CLASS="copyright"> |
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109 | Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at <A HREF="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</A>) |
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110 | </P> |
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111 | |
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