1407 lines
66 KiB
HTML
1407 lines
66 KiB
HTML
<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<!--[if IE]><meta http-equiv="X-UA-Compatible" content="IE=edge"><![endif]-->
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<meta name="generator" content="Asciidoctor 1.5.8">
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<meta name="author" content="Daryle Walker, Beman Dawes, Glen Joseph Fernandes <glenjofe@gmail.com>">
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<title>Boost.IO</title>
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<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans:300,300italic,400,400italic,600,600italic%7CNoto+Serif:400,400italic,700,700italic%7CDroid+Sans+Mono:400,700">
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<style>
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/* Asciidoctor default stylesheet | MIT License | http://asciidoctor.org */
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/* Uncomment @import statement below to use as custom stylesheet */
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/*@import "https://fonts.googleapis.com/css?family=Open+Sans:300,300italic,400,400italic,600,600italic%7CNoto+Serif:400,400italic,700,700italic%7CDroid+Sans+Mono:400,700";*/
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article,aside,details,figcaption,figure,footer,header,hgroup,main,nav,section,summary{display:block}
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audio,canvas,video{display:inline-block}
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audio:not([controls]){display:none;height:0}
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script{display:none!important}
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html{font-family:sans-serif;-ms-text-size-adjust:100%;-webkit-text-size-adjust:100%}
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a{background:transparent}
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a:focus{outline:thin dotted}
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a:active,a:hover{outline:0}
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h1{font-size:2em;margin:.67em 0}
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abbr[title]{border-bottom:1px dotted}
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b,strong{font-weight:bold}
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dfn{font-style:italic}
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hr{-moz-box-sizing:content-box;box-sizing:content-box;height:0}
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mark{background:#ff0;color:#000}
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code,kbd,pre,samp{font-family:monospace;font-size:1em}
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pre{white-space:pre-wrap}
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q{quotes:"\201C" "\201D" "\2018" "\2019"}
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small{font-size:80%}
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sub,sup{font-size:75%;line-height:0;position:relative;vertical-align:baseline}
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sup{top:-.5em}
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sub{bottom:-.25em}
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img{border:0}
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svg:not(:root){overflow:hidden}
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figure{margin:0}
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fieldset{border:1px solid silver;margin:0 2px;padding:.35em .625em .75em}
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legend{border:0;padding:0}
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button,input,select,textarea{font-family:inherit;font-size:100%;margin:0}
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button,input{line-height:normal}
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button,select{text-transform:none}
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button,html input[type="button"],input[type="reset"],input[type="submit"]{-webkit-appearance:button;cursor:pointer}
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button[disabled],html input[disabled]{cursor:default}
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input[type="checkbox"],input[type="radio"]{box-sizing:border-box;padding:0}
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button::-moz-focus-inner,input::-moz-focus-inner{border:0;padding:0}
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textarea{overflow:auto;vertical-align:top}
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table{border-collapse:collapse;border-spacing:0}
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*,*::before,*::after{-moz-box-sizing:border-box;-webkit-box-sizing:border-box;box-sizing:border-box}
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html,body{font-size:100%}
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body{background:#fff;color:rgba(0,0,0,.8);padding:0;margin:0;font-family:"Noto Serif","DejaVu Serif",serif;font-weight:400;font-style:normal;line-height:1;position:relative;cursor:auto;tab-size:4;-moz-osx-font-smoothing:grayscale;-webkit-font-smoothing:antialiased}
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a:hover{cursor:pointer}
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img,object,embed{max-width:100%;height:auto}
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object,embed{height:100%}
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img{-ms-interpolation-mode:bicubic}
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.left{float:left!important}
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.right{float:right!important}
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.text-left{text-align:left!important}
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.text-right{text-align:right!important}
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.text-center{text-align:center!important}
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.text-justify{text-align:justify!important}
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.hide{display:none}
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img,object,svg{display:inline-block;vertical-align:middle}
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textarea{height:auto;min-height:50px}
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select{width:100%}
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.center{margin-left:auto;margin-right:auto}
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.stretch{width:100%}
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.subheader,.admonitionblock td.content>.title,.audioblock>.title,.exampleblock>.title,.imageblock>.title,.listingblock>.title,.literalblock>.title,.stemblock>.title,.openblock>.title,.paragraph>.title,.quoteblock>.title,table.tableblock>.title,.verseblock>.title,.videoblock>.title,.dlist>.title,.olist>.title,.ulist>.title,.qlist>.title,.hdlist>.title{line-height:1.45;color:#7a2518;font-weight:400;margin-top:0;margin-bottom:.25em}
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div,dl,dt,dd,ul,ol,li,h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6,pre,form,p,blockquote,th,td{margin:0;padding:0;direction:ltr}
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a{color:#2156a5;text-decoration:underline;line-height:inherit}
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a:hover,a:focus{color:#1d4b8f}
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a img{border:none}
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p{font-family:inherit;font-weight:400;font-size:1em;line-height:1.6;margin-bottom:1.25em;text-rendering:optimizeLegibility}
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p aside{font-size:.875em;line-height:1.35;font-style:italic}
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h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{font-family:"Open Sans","DejaVu Sans",sans-serif;font-weight:300;font-style:normal;color:#ba3925;text-rendering:optimizeLegibility;margin-top:1em;margin-bottom:.5em;line-height:1.0125em}
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h1 small,h2 small,h3 small,#toctitle small,.sidebarblock>.content>.title small,h4 small,h5 small,h6 small{font-size:60%;color:#e99b8f;line-height:0}
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h1{font-size:2.125em}
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h2{font-size:1.6875em}
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h3,#toctitle,.sidebarblock>.content>.title{font-size:1.375em}
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h4,h5{font-size:1.125em}
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h6{font-size:1em}
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hr{border:solid #dddddf;border-width:1px 0 0;clear:both;margin:1.25em 0 1.1875em;height:0}
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em,i{font-style:italic;line-height:inherit}
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strong,b{font-weight:bold;line-height:inherit}
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small{font-size:60%;line-height:inherit}
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code{font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;font-weight:400;color:rgba(0,0,0,.9)}
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ul,ol,dl{font-size:1em;line-height:1.6;margin-bottom:1.25em;list-style-position:outside;font-family:inherit}
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ul,ol{margin-left:1.5em}
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ul li ul,ul li ol{margin-left:1.25em;margin-bottom:0;font-size:1em}
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ul.square li ul,ul.circle li ul,ul.disc li ul{list-style:inherit}
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ul.square{list-style-type:square}
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ul.circle{list-style-type:circle}
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ul.disc{list-style-type:disc}
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ol li ul,ol li ol{margin-left:1.25em;margin-bottom:0}
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dl dt{margin-bottom:.3125em;font-weight:bold}
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dl dd{margin-bottom:1.25em}
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abbr,acronym{text-transform:uppercase;font-size:90%;color:rgba(0,0,0,.8);border-bottom:1px dotted #ddd;cursor:help}
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abbr{text-transform:none}
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blockquote{margin:0 0 1.25em;padding:.5625em 1.25em 0 1.1875em;border-left:1px solid #ddd}
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blockquote cite{display:block;font-size:.9375em;color:rgba(0,0,0,.6)}
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blockquote cite::before{content:"\2014 \0020"}
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blockquote cite a,blockquote cite a:visited{color:rgba(0,0,0,.6)}
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blockquote,blockquote p{line-height:1.6;color:rgba(0,0,0,.85)}
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@media screen and (min-width:768px){h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{line-height:1.2}
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h1{font-size:2.75em}
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h2{font-size:2.3125em}
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h3,#toctitle,.sidebarblock>.content>.title{font-size:1.6875em}
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h4{font-size:1.4375em}}
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table{background:#fff;margin-bottom:1.25em;border:solid 1px #dedede}
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table thead,table tfoot{background:#f7f8f7}
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table thead tr th,table thead tr td,table tfoot tr th,table tfoot tr td{padding:.5em .625em .625em;font-size:inherit;color:rgba(0,0,0,.8);text-align:left}
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table tr th,table tr td{padding:.5625em .625em;font-size:inherit;color:rgba(0,0,0,.8)}
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table tr.even,table tr.alt,table tr:nth-of-type(even){background:#f8f8f7}
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table thead tr th,table tfoot tr th,table tbody tr td,table tr td,table tfoot tr td{display:table-cell;line-height:1.6}
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h1,h2,h3,#toctitle,.sidebarblock>.content>.title,h4,h5,h6{line-height:1.2;word-spacing:-.05em}
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h1 strong,h2 strong,h3 strong,#toctitle strong,.sidebarblock>.content>.title strong,h4 strong,h5 strong,h6 strong{font-weight:400}
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.clearfix::before,.clearfix::after,.float-group::before,.float-group::after{content:" ";display:table}
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.clearfix::after,.float-group::after{clear:both}
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*:not(pre)>code{font-size:.9375em;font-style:normal!important;letter-spacing:0;padding:.1em .5ex;word-spacing:-.15em;background-color:#f7f7f8;-webkit-border-radius:4px;border-radius:4px;line-height:1.45;text-rendering:optimizeSpeed;word-wrap:break-word}
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*:not(pre)>code.nobreak{word-wrap:normal}
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*:not(pre)>code.nowrap{white-space:nowrap}
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pre,pre>code{line-height:1.45;color:rgba(0,0,0,.9);font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;font-weight:400;text-rendering:optimizeSpeed}
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em em{font-style:normal}
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strong strong{font-weight:400}
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.keyseq{color:rgba(51,51,51,.8)}
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kbd{font-family:"Droid Sans Mono","DejaVu Sans Mono",monospace;display:inline-block;color:rgba(0,0,0,.8);font-size:.65em;line-height:1.45;background-color:#f7f7f7;border:1px solid #ccc;-webkit-border-radius:3px;border-radius:3px;-webkit-box-shadow:0 1px 0 rgba(0,0,0,.2),0 0 0 .1em white inset;box-shadow:0 1px 0 rgba(0,0,0,.2),0 0 0 .1em #fff inset;margin:0 .15em;padding:.2em .5em;vertical-align:middle;position:relative;top:-.1em;white-space:nowrap}
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.keyseq kbd:first-child{margin-left:0}
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.keyseq kbd:last-child{margin-right:0}
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.menuseq,.menuref{color:#000}
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.menuseq b:not(.caret),.menuref{font-weight:inherit}
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.menuseq{word-spacing:-.02em}
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.menuseq b.caret{font-size:1.25em;line-height:.8}
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.menuseq i.caret{font-weight:bold;text-align:center;width:.45em}
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b.button::before,b.button::after{position:relative;top:-1px;font-weight:400}
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b.button::before{content:"[";padding:0 3px 0 2px}
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b.button::after{content:"]";padding:0 2px 0 3px}
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p a>code:hover{color:rgba(0,0,0,.9)}
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#header,#content,#footnotes,#footer{width:100%;margin-left:auto;margin-right:auto;margin-top:0;margin-bottom:0;max-width:62.5em;*zoom:1;position:relative;padding-left:.9375em;padding-right:.9375em}
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#header::before,#header::after,#content::before,#content::after,#footnotes::before,#footnotes::after,#footer::before,#footer::after{content:" ";display:table}
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#header::after,#content::after,#footnotes::after,#footer::after{clear:both}
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#content{margin-top:1.25em}
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#content::before{content:none}
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#header>h1:first-child{color:rgba(0,0,0,.85);margin-top:2.25rem;margin-bottom:0}
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#header>h1:first-child+#toc{margin-top:8px;border-top:1px solid #dddddf}
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#header>h1:only-child,body.toc2 #header>h1:nth-last-child(2){border-bottom:1px solid #dddddf;padding-bottom:8px}
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#header .details{border-bottom:1px solid #dddddf;line-height:1.45;padding-top:.25em;padding-bottom:.25em;padding-left:.25em;color:rgba(0,0,0,.6);display:-ms-flexbox;display:-webkit-flex;display:flex;-ms-flex-flow:row wrap;-webkit-flex-flow:row wrap;flex-flow:row wrap}
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#header .details span:first-child{margin-left:-.125em}
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#header .details span.email a{color:rgba(0,0,0,.85)}
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#header .details br{display:none}
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#header .details br+span::before{content:"\00a0\2013\00a0"}
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#header .details br+span.author::before{content:"\00a0\22c5\00a0";color:rgba(0,0,0,.85)}
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#header .details br+span#revremark::before{content:"\00a0|\00a0"}
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#header #revnumber{text-transform:capitalize}
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#header #revnumber::after{content:"\00a0"}
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#content>h1:first-child:not([class]){color:rgba(0,0,0,.85);border-bottom:1px solid #dddddf;padding-bottom:8px;margin-top:0;padding-top:1rem;margin-bottom:1.25rem}
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#toc{border-bottom:1px solid #e7e7e9;padding-bottom:.5em}
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#toc>ul{margin-left:.125em}
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#toc ul.sectlevel0>li>a{font-style:italic}
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#toc ul.sectlevel0 ul.sectlevel1{margin:.5em 0}
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#toc ul{font-family:"Open Sans","DejaVu Sans",sans-serif;list-style-type:none}
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#toc li{line-height:1.3334;margin-top:.3334em}
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#toc a{text-decoration:none}
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#toc a:active{text-decoration:underline}
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#toctitle{color:#7a2518;font-size:1.2em}
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@media screen and (min-width:768px){#toctitle{font-size:1.375em}
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body.toc2{padding-left:15em;padding-right:0}
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#toc.toc2{margin-top:0!important;background-color:#f8f8f7;position:fixed;width:15em;left:0;top:0;border-right:1px solid #e7e7e9;border-top-width:0!important;border-bottom-width:0!important;z-index:1000;padding:1.25em 1em;height:100%;overflow:auto}
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#toc.toc2 #toctitle{margin-top:0;margin-bottom:.8rem;font-size:1.2em}
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#toc.toc2>ul{font-size:.9em;margin-bottom:0}
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#toc.toc2 ul ul{margin-left:0;padding-left:1em}
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body.toc2.toc-right{padding-left:0;padding-right:15em}
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body.toc2.toc-right #toc.toc2{border-right-width:0;border-left:1px solid #e7e7e9;left:auto;right:0}}
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@media screen and (min-width:1280px){body.toc2{padding-left:20em;padding-right:0}
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#toc.toc2{width:20em}
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#toc.toc2 #toctitle{font-size:1.375em}
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#toc.toc2>ul{font-size:.95em}
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#toc.toc2 ul ul{padding-left:1.25em}
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body.toc2.toc-right{padding-left:0;padding-right:20em}}
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#content #toc{border-style:solid;border-width:1px;border-color:#e0e0dc;margin-bottom:1.25em;padding:1.25em;background:#f8f8f7;-webkit-border-radius:4px;border-radius:4px}
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#content #toc>:first-child{margin-top:0}
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#content #toc>:last-child{margin-bottom:0}
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#footer{max-width:100%;background-color:rgba(0,0,0,.8);padding:1.25em}
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#footer-text{color:rgba(255,255,255,.8);line-height:1.44}
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#content{margin-bottom:.625em}
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.sect1{padding-bottom:.625em}
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@media screen and (min-width:768px){#content{margin-bottom:1.25em}
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.sect1{padding-bottom:1.25em}}
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.sect1:last-child{padding-bottom:0}
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.sect1+.sect1{border-top:1px solid #e7e7e9}
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#content h1>a.anchor,h2>a.anchor,h3>a.anchor,#toctitle>a.anchor,.sidebarblock>.content>.title>a.anchor,h4>a.anchor,h5>a.anchor,h6>a.anchor{position:absolute;z-index:1001;width:1.5ex;margin-left:-1.5ex;display:block;text-decoration:none!important;visibility:hidden;text-align:center;font-weight:400}
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#content h1>a.anchor::before,h2>a.anchor::before,h3>a.anchor::before,#toctitle>a.anchor::before,.sidebarblock>.content>.title>a.anchor::before,h4>a.anchor::before,h5>a.anchor::before,h6>a.anchor::before{content:"\00A7";font-size:.85em;display:block;padding-top:.1em}
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#content h1>a.link,h2>a.link,h3>a.link,#toctitle>a.link,.sidebarblock>.content>.title>a.link,h4>a.link,h5>a.link,h6>a.link{color:#ba3925;text-decoration:none}
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#content h1>a.link:hover,h2>a.link:hover,h3>a.link:hover,#toctitle>a.link:hover,.sidebarblock>.content>.title>a.link:hover,h4>a.link:hover,h5>a.link:hover,h6>a.link:hover{color:#a53221}
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.audioblock,.imageblock,.literalblock,.listingblock,.stemblock,.videoblock{margin-bottom:1.25em}
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table.tableblock.fit-content>caption.title{white-space:nowrap;width:0}
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.paragraph.lead>p,#preamble>.sectionbody>[class="paragraph"]:first-of-type p{font-size:1.21875em;line-height:1.6;color:rgba(0,0,0,.85)}
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table.tableblock #preamble>.sectionbody>[class="paragraph"]:first-of-type p{font-size:inherit}
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.admonitionblock>table{border-collapse:separate;border:0;background:none;width:100%}
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.admonitionblock>table td.icon{text-align:center;width:80px}
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.admonitionblock>table td.icon img{max-width:none}
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.admonitionblock>table td.icon .title{font-weight:bold;font-family:"Open Sans","DejaVu Sans",sans-serif;text-transform:uppercase}
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.admonitionblock>table td.content{padding-left:1.125em;padding-right:1.25em;border-left:1px solid #dddddf;color:rgba(0,0,0,.6)}
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.admonitionblock>table td.content>:last-child>:last-child{margin-bottom:0}
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.exampleblock>.content{border-style:solid;border-width:1px;border-color:#e6e6e6;margin-bottom:1.25em;padding:1.25em;background:#fff;-webkit-border-radius:4px;border-radius:4px}
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.exampleblock>.content>:first-child{margin-top:0}
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.exampleblock>.content>:last-child{margin-bottom:0}
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.sidebarblock{border-style:solid;border-width:1px;border-color:#e0e0dc;margin-bottom:1.25em;padding:1.25em;background:#f8f8f7;-webkit-border-radius:4px;border-radius:4px}
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.sidebarblock>:first-child{margin-top:0}
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.sidebarblock>:last-child{margin-bottom:0}
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.sidebarblock>.content>.title{color:#7a2518;margin-top:0;text-align:center}
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.exampleblock>.content>:last-child>:last-child,.exampleblock>.content .olist>ol>li:last-child>:last-child,.exampleblock>.content .ulist>ul>li:last-child>:last-child,.exampleblock>.content .qlist>ol>li:last-child>:last-child,.sidebarblock>.content>:last-child>:last-child,.sidebarblock>.content .olist>ol>li:last-child>:last-child,.sidebarblock>.content .ulist>ul>li:last-child>:last-child,.sidebarblock>.content .qlist>ol>li:last-child>:last-child{margin-bottom:0}
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.literalblock pre,.listingblock pre:not(.highlight),.listingblock pre[class="highlight"],.listingblock pre[class^="highlight "],.listingblock pre.CodeRay,.listingblock pre.prettyprint{background:#f7f7f8}
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.sidebarblock .literalblock pre,.sidebarblock .listingblock pre:not(.highlight),.sidebarblock .listingblock pre[class="highlight"],.sidebarblock .listingblock pre[class^="highlight "],.sidebarblock .listingblock pre.CodeRay,.sidebarblock .listingblock pre.prettyprint{background:#f2f1f1}
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</style>
|
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</head>
|
|
<body class="article toc2 toc-left">
|
|
<div id="header">
|
|
<h1>Boost.IO</h1>
|
|
<div class="details">
|
|
<span id="author" class="author">Daryle Walker, Beman Dawes, Glen Joseph Fernandes <glenjofe@gmail.com></span><br>
|
|
</div>
|
|
<div id="toc" class="toc2">
|
|
<div id="toctitle">Table of Contents</div>
|
|
<ul class="sectlevel1">
|
|
<li><a href="#io_state_savers_boostioios_state_hpp">IO State Savers, <boost/io/ios_state.hpp></a>
|
|
<ul class="sectlevel2">
|
|
<li><a href="#description">Description</a></li>
|
|
<li><a href="#rationale">Rationale</a></li>
|
|
<li><a href="#header_synopsis">Header Synopsis</a></li>
|
|
<li><a href="#savers_for_basic_standard_attributes">Savers for Basic Standard Attributes</a></li>
|
|
<li><a href="#savers_for_advanced_standard_attributes">Savers for Advanced Standard Attributes</a></li>
|
|
<li><a href="#savers_for_user_defined_attributes">Savers for User-Defined Attributes</a></li>
|
|
<li><a href="#example">Example</a></li>
|
|
<li><a href="#credits">Credits</a></li>
|
|
<li><a href="#history">History</a></li>
|
|
</ul>
|
|
</li>
|
|
<li><a href="#quoted_manipulators_boostioquoted_hpp">Quoted Manipulators, <boost/io/quoted.hpp></a>
|
|
<ul class="sectlevel2">
|
|
<li><a href="#introduction">Introduction</a></li>
|
|
<li><a href="#header_synopsis_2">Header synopsis</a></li>
|
|
<li><a href="#acknowledgements">Acknowledgements</a></li>
|
|
</ul>
|
|
</li>
|
|
<li><a href="#delimited_iterators_boostioostream_joiner_hpp">Delimited Iterators, <boost/io/ostream_joiner.hpp></a>
|
|
<ul class="sectlevel2">
|
|
<li><a href="#description_2">Description</a></li>
|
|
<li><a href="#example_2">Example</a></li>
|
|
<li><a href="#reference">Reference</a></li>
|
|
<li><a href="#acknowledgments">Acknowledgments</a></li>
|
|
</ul>
|
|
</li>
|
|
<li><a href="#insert_formatted_output_boostioostream_put_hpp">Insert Formatted Output, <boost/io/ostream_put.hpp></a>
|
|
<ul class="sectlevel2">
|
|
<li><a href="#description_3">Description</a></li>
|
|
<li><a href="#example_3">Example</a></li>
|
|
<li><a href="#reference_2">Reference</a></li>
|
|
<li><a href="#acknowledgments_2">Acknowledgments</a></li>
|
|
</ul>
|
|
</li>
|
|
<li><a href="#copyright_and_license">Copyright and License</a></li>
|
|
</ul>
|
|
</div>
|
|
</div>
|
|
<div id="content">
|
|
<div id="preamble">
|
|
<div class="sectionbody">
|
|
<div class="paragraph">
|
|
<p>This library contains various utilities for the standard I/O library.</p>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="sect1">
|
|
<h2 id="io_state_savers_boostioios_state_hpp">IO State Savers, <boost/io/ios_state.hpp></h2>
|
|
<div class="sectionbody">
|
|
<div class="sect2">
|
|
<h3 id="description">Description</h3>
|
|
<div class="paragraph">
|
|
<p>The header <code><boost/io/ios_state.hpp></code> covers saving the stream state of objects
|
|
in the C++ IOStreams system.</p>
|
|
</div>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="rationale">Rationale</h3>
|
|
<div class="paragraph">
|
|
<p>Sometimes a certain value has to change only for a limited scope. Saver classes
|
|
save a copy of the current state of some object (or an aspect of an object),
|
|
and reset the object’s state at destruction time, undoing any change the object
|
|
may have gone through.</p>
|
|
</div>
|
|
<div class="paragraph">
|
|
<p>The saver class strategy is helpful when using I/O stream objects. Manipulator
|
|
objects can change some aspect of a stream during input or output. The state
|
|
changed by the manipulator usually sticks to its new value after the I/O
|
|
transaction. This can be a problem if manipulators are used in a function that
|
|
is not supposed to externally change a stream’s state.</p>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">#include <ostream>
|
|
#include <ios>
|
|
|
|
void hex_my_byte(std::ostream& os, char byte)
|
|
{
|
|
os << std::hex << static_cast<unsigned>(byte);
|
|
}</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="paragraph">
|
|
<p>The <code>os</code> stream will retain its new hexadecimal printing mode after the call to
|
|
<code>hex_my_byte</code>. The stream’s printing mode can be saved and restored with manual
|
|
calls to the stream’s state inspecting and mutating member functions. The
|
|
manual method becomes unwieldy if the main functionality is complex and/or
|
|
needs to be exception safe. A saver class can implement the better
|
|
"resource acquisition is initialization" strategy.</p>
|
|
</div>
|
|
<div class="paragraph">
|
|
<p>See the example below for better code, using saver classes.</p>
|
|
</div>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="header_synopsis">Header Synopsis</h3>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">namespace boost {
|
|
namespace io {
|
|
|
|
class ios_flags_saver;
|
|
class ios_precision_saver;
|
|
class ios_width_saver;
|
|
class ios_base_all_saver;
|
|
|
|
template<class Ch, class Tr = std::char_traits<Ch> >
|
|
class basic_ios_iostate_saver;
|
|
|
|
template<class Ch, class Tr = std::char_traits<Ch> >
|
|
class basic_ios_exception_saver;
|
|
|
|
template<class Ch, class Tr = std::char_traits<Ch> >
|
|
class basic_ios_tie_saver;
|
|
|
|
template<class Ch, class Tr = std::char_traits<Ch> >
|
|
class basic_ios_rdbuf_saver;
|
|
|
|
template<class Ch, class Tr = std::char_traits<Ch> >
|
|
class basic_ios_fill_saver;
|
|
|
|
template<class Ch, class Tr = std::char_traits<Ch> >
|
|
class basic_ios_locale_saver;
|
|
|
|
template<class Ch, class Tr = std::char_traits<Ch> >
|
|
class basic_ios_all_saver;
|
|
|
|
typedef basic_ios_iostate_saver<char> ios_iostate_saver;
|
|
typedef basic_ios_iostate_saver<wchar_t> wios_iostate_saver;
|
|
typedef basic_ios_exception_saver<char> ios_exception_saver;
|
|
typedef basic_ios_exception_saver<wchar_t> wios_exception_saver;
|
|
typedef basic_ios_tie_saver<char> ios_tie_saver;
|
|
typedef basic_ios_tie_saver<wchar_t> wios_tie_saver;
|
|
typedef basic_ios_rdbuf_saver<char> ios_rdbuf_saver;
|
|
typedef basic_ios_rdbuf_saver<wchar_t> wios_rdbuf_saver;
|
|
typedef basic_ios_fill_saver<char> ios_fill_saver;
|
|
typedef basic_ios_fill_saver<wchar_t> wios_fill_saver;
|
|
typedef basic_ios_locale_saver<char> ios_locale_saver;
|
|
typedef basic_ios_locale_saver<wchar_t> wios_locale_saver;
|
|
typedef basic_ios_all_saver<char> ios_all_saver;
|
|
typedef basic_ios_all_saver<wchar_t> wios_all_saver;
|
|
|
|
class ios_iword_saver;
|
|
class ios_pword_saver;
|
|
class ios_all_word_saver;
|
|
|
|
} // io
|
|
} // boost</code></pre>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="savers_for_basic_standard_attributes">Savers for Basic Standard Attributes</h3>
|
|
<div class="paragraph">
|
|
<p>The basic saver classes have this format:</p>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">class saver {
|
|
public:
|
|
typedef std::ios_base state_type;
|
|
typedef <code>implementation_defined</code> aspect_type;
|
|
|
|
explicit saver(state_type& s);
|
|
saver(state_type& s, const aspect_type& new_value);
|
|
~saver();
|
|
|
|
void restore();
|
|
};</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="paragraph">
|
|
<p>The <code>state_type</code> is the IOStreams base class <code>std::ios_base</code>. The user would
|
|
usually place an actual input, output, or combined stream object for the
|
|
state-type parameter, and not a base class object. The first constructor takes
|
|
a stream object and saves a reference to the stream and the current value of a
|
|
particular stream attribute. The second constructor works like the first, and
|
|
uses its second argument to change the stream’s attribute to the new
|
|
<code>aspect_type</code> value given. The destructor restores the stream’s attribute to
|
|
the saved value. The restoration can be activated early (and often) with the
|
|
<code>restore</code> member function.</p>
|
|
</div>
|
|
<table class="tableblock frame-all grid-all stretch">
|
|
<caption class="title">Table 1. Basic IOStreams State Saver Classes</caption>
|
|
<colgroup>
|
|
<col style="width: 20%;">
|
|
<col style="width: 20%;">
|
|
<col style="width: 20%;">
|
|
<col style="width: 20%;">
|
|
<col style="width: 20%;">
|
|
</colgroup>
|
|
<thead>
|
|
<tr>
|
|
<th class="tableblock halign-left valign-top">Class</th>
|
|
<th class="tableblock halign-left valign-top">Saved Attribute</th>
|
|
<th class="tableblock halign-left valign-top">Attribute Type</th>
|
|
<th class="tableblock halign-left valign-top">Reading Method</th>
|
|
<th class="tableblock halign-left valign-top">Writing Method</th>
|
|
</tr>
|
|
</thead>
|
|
<tbody>
|
|
<tr>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>ios_flags_saver</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock">Format control flags</p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>std::ios_base::fmtflags</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>flags</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>flags</code></p></td>
|
|
</tr>
|
|
<tr>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>ios_precision_saver</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock">Number of digits to print after decimal point</p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>std::streamsize</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>precision</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>precision</code></p></td>
|
|
</tr>
|
|
<tr>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>ios_width_saver</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock">Minimum field width for printing objects</p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>std::streamsize</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>width</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>width</code></p></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="savers_for_advanced_standard_attributes">Savers for Advanced Standard Attributes</h3>
|
|
<div class="paragraph">
|
|
<p>The saver class templates have this format:</p>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">template<class Ch, class Tr>
|
|
class saver {
|
|
public:
|
|
typedef std::basic_ios<Ch, Tr> state_type;
|
|
typedef <code>implementation-defined</code> aspect_type;
|
|
|
|
explicit saver(state_type& s);
|
|
saver(state_type& s, const aspect_type& new_value);
|
|
~saver();
|
|
|
|
void restore();
|
|
};</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="paragraph">
|
|
<p>The <code>state_type</code> is a version of the IOStreams base class template
|
|
<code>std::basic_ios<Ch, Tr></code>, where <code>Ch</code> is a character type and <code>Tr</code> is a
|
|
character traits class. The user would usually place an actual input,
|
|
output, or combined stream object for the state-type parameter, and not a base
|
|
class object. The first constructor takes a stream object and saves a reference
|
|
to the stream and the current value of a particular stream attribute. The
|
|
second constructor works like the first, and uses its second argument to change
|
|
the stream’s attribute to the new <code>aspect_type</code> value given. The destructor
|
|
restores the stream’s attribute to the saved value. The restoration can be
|
|
activated early (and often) with the <code>restore</code> member function.</p>
|
|
</div>
|
|
<table class="tableblock frame-all grid-all stretch">
|
|
<caption class="title">Table 2. Advanced IOStreams State Saver Class Templates</caption>
|
|
<colgroup>
|
|
<col style="width: 20%;">
|
|
<col style="width: 20%;">
|
|
<col style="width: 20%;">
|
|
<col style="width: 20%;">
|
|
<col style="width: 20%;">
|
|
</colgroup>
|
|
<thead>
|
|
<tr>
|
|
<th class="tableblock halign-left valign-top">Class</th>
|
|
<th class="tableblock halign-left valign-top">Saved Attribute</th>
|
|
<th class="tableblock halign-left valign-top">Attribute Type</th>
|
|
<th class="tableblock halign-left valign-top">Reading Method</th>
|
|
<th class="tableblock halign-left valign-top">Writing Method</th>
|
|
</tr>
|
|
</thead>
|
|
<tbody>
|
|
<tr>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>basic_ios_iostate_saver<Ch, Tr></code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock">Failure state of the stream [1], [2]</p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>std::ios_base::iostate</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>rdstate</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>clear</code></p></td>
|
|
</tr>
|
|
<tr>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>basic_ios_exception_saver<Ch, Tr></code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock">Which failure states trigger an exception [1]</p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>std::ios_base::iostate</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>exceptions</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>exceptions</code></p></td>
|
|
</tr>
|
|
<tr>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>basic_ios_tie_saver<Ch, Tr></code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock">Output stream synchronized with the stream</p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>std::basic_ostream<Ch, Tr>*</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>tie</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>tie</code></p></td>
|
|
</tr>
|
|
<tr>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>basic_ios_rdbuf_saver<Ch, Tr></code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock">Stream buffer associated with the stream [2]</p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>std::basic_streambuf<Ch, Tr>*</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>rdbuf</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>rdbuf</code></p></td>
|
|
</tr>
|
|
<tr>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>basic_ios_fill_saver<Ch, Tr></code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock">Character used to pad oversized field widths</p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>Ch</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>fill</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>fill</code></p></td>
|
|
</tr>
|
|
<tr>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>basic_ios_locale_saver<Ch, Tr></code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock">Locale information associated with the stream [3]</p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>std::locale</code></p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>getloc</code> (from <code>std::ios_base</code>)</p></td>
|
|
<td class="tableblock halign-left valign-top"><p class="tableblock"><code>imbue</code> (from <code>std::basic_ios<Ch, Tr></code>)</p></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<div class="sect3">
|
|
<h4 id="notes">Notes</h4>
|
|
<div class="olist arabic">
|
|
<ol class="arabic">
|
|
<li>
|
|
<p>When the failure state flags and/or the failure state exception watching
|
|
flags are changed, an exception is thrown if a match occurs among the two sets
|
|
of flags. This could mean that the constructor or destructor of these class
|
|
templates may throw.</p>
|
|
</li>
|
|
<li>
|
|
<p>When the associated stream buffer is changed, the stream’s failure state set
|
|
is reset to "good" if the given stream buffer’s address is non-NULL, but the
|
|
"bad" failure state is set if that address is NULL. This means that a saved
|
|
failure state of "good" may be restored as "bad" if the stream is stripped of
|
|
an associated stream buffer. Worse, given a NULL stream buffer address, an
|
|
exception is thrown if the "bad" failure state is being watched. This could
|
|
mean that the constructor or destructor of these class templates may throw.</p>
|
|
</li>
|
|
<li>
|
|
<p>The saver for the locale uses the <code>std::basic_ios<Ch, Tr></code> class to extract
|
|
their information, although it could have used the functionality in
|
|
<code>std::ios_base</code>. The problem is that the versions of the needed member
|
|
functions in <code>ios_base</code> are not polymorphically related to the ones in
|
|
<code>basic_ios</code>. The stream classes that will be used with the saver classes should
|
|
use the versions of the member functions closest to them by inheritance, which
|
|
means the ones in <code>basic_ios</code>.</p>
|
|
</li>
|
|
</ol>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="savers_for_user_defined_attributes">Savers for User-Defined Attributes</h3>
|
|
<div class="paragraph">
|
|
<p>There are three class (templates) for combined attribute savers. The
|
|
<code>ios_base_all_saver</code> saver class combines the functionality of all the basic
|
|
attribute saver classes. It has a constructor that takes the stream to have its
|
|
state preserved. The <code>basic_ios_all_saver</code> combines the functionality of all
|
|
the advanced attribute saver class templates and the combined basic attribute
|
|
saver class. It has a constructor that takes the stream to have its state
|
|
preserved. The <code>ios_all_word_saver</code> saver class combines the saver classes that
|
|
preserve user-defined formatting information. Its constructor takes the stream
|
|
to have its attributes saved and the index of the user-defined attributes. The
|
|
destructor for each class restores the saved state. Restoration can be
|
|
activated early (and often) for a class with the restore member function.</p>
|
|
</div>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="example">Example</h3>
|
|
<div class="paragraph">
|
|
<p>The code used in the rationale can be improved at two places. The printing
|
|
function could use a saver around the code that changes the formatting state.
|
|
Or the calling function can surround the call with a saver. Or both can be
|
|
done, especially if the user does not know if the printing function uses a
|
|
state saver. If the user wants a series of changes back and forth, without
|
|
surrounding each change within a separate block, the restore member function
|
|
can be called between each trial.</p>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">#include <boost/io/ios_state.hpp>
|
|
#include <ios>
|
|
#include <iostream>
|
|
#include <ostream>
|
|
|
|
void new_hex_my_byte(std::ostream& os, char byte)
|
|
{
|
|
boost::io::ios_flags_saver ifs(os);
|
|
os << std::hex << static_cast<unsigned>(byte);
|
|
}
|
|
|
|
int main()
|
|
{
|
|
// ...
|
|
{
|
|
boost::io::ios_all_saver ias(std::cout);
|
|
new_hex_my_byte(std::cout, 'A');
|
|
}
|
|
// ...
|
|
{
|
|
boost::io::ios_all_saver ias(std::cerr);
|
|
new_hex_my_byte(std::cerr, 'b');
|
|
ias.restore();
|
|
new_hex_my_byte(std::cerr, 'C');
|
|
}
|
|
// ...
|
|
}</code></pre>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="credits">Credits</h3>
|
|
<div class="sect3">
|
|
<h4 id="daryle_walker">Daryle Walker</h4>
|
|
<div class="paragraph">
|
|
<p>Started the library. Contributed the initial versions of the format flags,
|
|
precision, width, and user-defined format flags saver classes. Contributed the
|
|
initial versions of the success state, success state exception flags, output
|
|
stream tie, stream buffer, character fill, and locale saver class templates.
|
|
Contributed the combined attribute classes and class template. Contributed the
|
|
test file <code>ios_state_test.cpp</code>.</p>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="history">History</h3>
|
|
<div class="sect3">
|
|
<h4 id="20_dec_2019">20 Dec 2019</h4>
|
|
<div class="paragraph">
|
|
<p>Glen Fernandes made all the saver classes non-copyable.</p>
|
|
</div>
|
|
</div>
|
|
<div class="sect3">
|
|
<h4 id="28_feb_2005">28 Feb 2005</h4>
|
|
<div class="paragraph">
|
|
<p>Daryle Walker added the restore member functions, based on suggestions by
|
|
Gennadiy Rozental and Rob Stewart.</p>
|
|
</div>
|
|
</div>
|
|
<div class="sect3">
|
|
<h4 id="13_mar_2002">13 Mar 2002</h4>
|
|
<div class="paragraph">
|
|
<p>Daryle Walker implemented the initial version.</p>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="sect1">
|
|
<h2 id="quoted_manipulators_boostioquoted_hpp">Quoted Manipulators, <boost/io/quoted.hpp></h2>
|
|
<div class="sectionbody">
|
|
<div class="sect2">
|
|
<h3 id="introduction">Introduction</h3>
|
|
<div class="paragraph">
|
|
<p>C++ Standard library stream I/O for strings that contain embedded spaces can
|
|
produce unexpected results. For example,</p>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">std::stringstream ss;
|
|
std::string original = "fooled you";
|
|
std::string roundtrip;
|
|
|
|
ss << original;
|
|
ss >> roundtrip;
|
|
|
|
std::cout << original; // outputs: fooled you
|
|
std::cout << roundtrip; // outputs: fooled
|
|
|
|
assert(original == roundtrip); // assert will fire</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="paragraph">
|
|
<p>The Boost quoted stream I/O manipulator places delimiters, defaulted to the
|
|
double-quote ("), around strings on output, and strips off the delimiters on
|
|
input. This ensures strings with embedded spaces round-trip as desired. For
|
|
example,</p>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">std::stringstream ss;
|
|
std::string original = "fooled you";
|
|
std::string roundtrip;
|
|
|
|
ss << quoted(original);
|
|
ss >> quoted(roundtrip);
|
|
|
|
std::cout << quoted(original); // outputs: "fooled you"
|
|
std::cout << roundtrip; // outputs: fooled you
|
|
|
|
assert(original == roundtrip); // assert will not fire</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="paragraph">
|
|
<p>If the string contains the delimiter character, on output that character will
|
|
be preceded by an escape character, as will the escape character itself:</p>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">std::cout << quoted("'Jack & Jill'", '&', '\''); // outputs: '&'Jack && Jill&''</code></pre>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="header_synopsis_2">Header synopsis</h3>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">namespace boost {
|
|
namespace io {
|
|
|
|
template<class Char, class Traits, class Alloc>
|
|
<code>unspecified-type1</code>
|
|
quoted(const std::basic_string<Char, Traits, Alloc>& string,
|
|
Char escape='\\', Char delim='\"');
|
|
|
|
template<class Char>
|
|
<code>unspecified-type2</code>
|
|
quoted(const Char* string, Char escape='\\', Char delim='\"');
|
|
|
|
template<class Char, class Traits, class Alloc>
|
|
<code>unspecified-type3</code>
|
|
quoted(std::basic_string<Char, Traits, Alloc>& string,
|
|
Char escape='\\', Char delim='\"');
|
|
|
|
} // io
|
|
} // boost</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="paragraph">
|
|
<p><strong>unspecified-type1</strong>, <strong>unspecified-type2</strong>, and <strong>unspecified-type3</strong> are
|
|
implementation supplied types with implementation supplied <code>operator<<</code>:</p>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">template<class Char, class Traits>
|
|
std::basic_ostream<Char, Traits>&
|
|
operator<<(std::basic_ostream<Char, Traits>& os,
|
|
const <code>unspecified-typeN</code>& proxy);</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="dlist">
|
|
<dl>
|
|
<dt class="hdlist1">Effects</dt>
|
|
<dd>
|
|
<p>Inserts characters into <code>os</code>:</p>
|
|
<div class="ulist">
|
|
<ul>
|
|
<li>
|
|
<p><code>delim</code></p>
|
|
</li>
|
|
<li>
|
|
<p>Each character in <code>string</code>. If the character to be output is equal to
|
|
<code>escape</code> or <code>delim</code>, as determined by <code>operator==</code>, first output <code>escape</code>.</p>
|
|
</li>
|
|
<li>
|
|
<p><code>delim</code></p>
|
|
</li>
|
|
</ul>
|
|
</div>
|
|
</dd>
|
|
<dt class="hdlist1">Remarks</dt>
|
|
<dd>
|
|
<p><code>string</code>, <code>escape</code>, and <code>delim</code> have the type and value of the
|
|
corresponding arguments of the call to the <code>quoted</code> function that constructed
|
|
<code>proxy</code>.</p>
|
|
</dd>
|
|
<dt class="hdlist1">Returns</dt>
|
|
<dd>
|
|
<p><code>os</code>.</p>
|
|
</dd>
|
|
</dl>
|
|
</div>
|
|
<div class="paragraph">
|
|
<p><strong>unspecified-type3</strong> is an implementation supplied type with an implementation
|
|
supplied <code>operator>></code>:</p>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">template<class Char, class Traits>
|
|
std::basic_istream<Char, Traits>&
|
|
operator>>(std::basic_istream<Char, Traits>& is,
|
|
const <code>unspecified-type3</code>& proxy);</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="dlist">
|
|
<dl>
|
|
<dt class="hdlist1">Effects</dt>
|
|
<dd>
|
|
<p>Extracts characters from <code>os</code>:</p>
|
|
<div class="ulist">
|
|
<ul>
|
|
<li>
|
|
<p>If the first character extracted is equal to <code>delim</code>, as determined by
|
|
<code>operator==</code>, then:</p>
|
|
<div class="ulist">
|
|
<ul>
|
|
<li>
|
|
<p>Turn off the <code>skipws</code> flag.</p>
|
|
</li>
|
|
<li>
|
|
<p><code>string.clear()</code></p>
|
|
</li>
|
|
<li>
|
|
<p>Until an unescaped <code>delim</code> character is reached or <code>is.not_good()</code>, extract
|
|
characters from <code>os</code> and append them to string, except that if an escape is
|
|
reached, ignore it and append the next character to string.</p>
|
|
</li>
|
|
<li>
|
|
<p>Discard the final <code>delim</code> character.</p>
|
|
</li>
|
|
<li>
|
|
<p>Restore the <code>skipws</code> flag to its original value.</p>
|
|
</li>
|
|
</ul>
|
|
</div>
|
|
</li>
|
|
<li>
|
|
<p>Otherwise, <code>os >> string</code>.</p>
|
|
</li>
|
|
</ul>
|
|
</div>
|
|
</dd>
|
|
<dt class="hdlist1">Remarks</dt>
|
|
<dd>
|
|
<p><code>string</code>, <code>escape</code>, and <code>delim</code> have the type and value of the
|
|
corresponding arguments of the call to the <code>quoted</code> function that constructed
|
|
<code>proxy</code>.</p>
|
|
</dd>
|
|
<dt class="hdlist1">Returns</dt>
|
|
<dd>
|
|
<p><code>is</code>.</p>
|
|
</dd>
|
|
</dl>
|
|
</div>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="acknowledgements">Acknowledgements</h3>
|
|
<div class="paragraph">
|
|
<p>The <code>quoted()</code> stream manipulator emerged from discussions on the Boost
|
|
developers mailing list. Participants included Beman Dawes, Rob Stewart,
|
|
Alexander Lamaison, Eric Niebler, Vicente Botet, Andrey Semashev,
|
|
Phil Richards, and Rob Murray. Eric Niebler’s suggestions provided the basis
|
|
for the name and form of the templates.</p>
|
|
</div>
|
|
<div class="paragraph">
|
|
<p>Beman Dawes started the implementation of <code>quoted()</code> as a private detail
|
|
header. Glen Fernandes updated the implementation and also made it public.</p>
|
|
</div>
|
|
<div class="paragraph">
|
|
<p>Glen Fernandes corrected the implementation to properly account for stream
|
|
width and fill, and optimized it to write directly to the stream buffer.</p>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="sect1">
|
|
<h2 id="delimited_iterators_boostioostream_joiner_hpp">Delimited Iterators, <boost/io/ostream_joiner.hpp></h2>
|
|
<div class="sectionbody">
|
|
<div class="sect2">
|
|
<h3 id="description_2">Description</h3>
|
|
<div class="paragraph">
|
|
<p>The header <code><boost/io/ostream_joiner.hpp></code> provides the class template
|
|
<code>boost::io::ostream_joiner</code> which is an output iterator that writes objects to
|
|
a <code>std::basic_ostream</code> separated by a delimiter. It is an implementation of
|
|
the Library Fundamentals TS <code>std::ostream_joiner</code> which supports C++03 and
|
|
higher.</p>
|
|
</div>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="example_2">Example</h3>
|
|
<div class="paragraph">
|
|
<p>The following program writes the contents of a vector to standard output, with
|
|
each element separated by a comma.</p>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">#include <boost/io/ostream_joiner.hpp>
|
|
#include <algorithm>
|
|
#include <iostream>
|
|
#include <vector>
|
|
|
|
int main()
|
|
{
|
|
std::vector<int> v;
|
|
v.push_back(2);
|
|
v.push_back(4);
|
|
v.push_back(6);
|
|
v.push_back(8);
|
|
std::copy(v.begin(), v.end(), boost::make_ostream_joiner(std::cout, ','));
|
|
}</code></pre>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="reference">Reference</h3>
|
|
<div class="sect3">
|
|
<h4 id="header_synopsis_3">Header Synopsis</h4>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">namespace boost {
|
|
namespace io {
|
|
|
|
template<class Delim, class Char = char,
|
|
class Traits = std::char_traits<Char> >
|
|
class ostream_joiner {
|
|
public:
|
|
typedef Char char_type;
|
|
typedef Traits traits_type;
|
|
typedef std::basic_ostream<Char, Traits> ostream_type;
|
|
typedef std::output_iterator_tag iterator_category;
|
|
typedef void value_type;
|
|
typedef void difference_type;
|
|
typedef void pointer;
|
|
typedef void reference;
|
|
|
|
ostream_joiner(ostream_type& output, const Delim& delim);
|
|
ostream_joiner(ostream_type& output, Delim&& delim);
|
|
|
|
template<class T>
|
|
ostream_joiner& operator=(const T& value);
|
|
|
|
ostream_joiner& operator*() noexcept;
|
|
ostream_joiner& operator++() noexcept;
|
|
ostream_joiner& operator++(int) noexcept;
|
|
};
|
|
|
|
template<class Char, class Traits, class Delim>
|
|
ostream_joiner<std::decay_t<Delim>, Char, Traits>
|
|
make_ostream_joiner(std::basic_ostream<Char, Traits>& output, Delim&& delim);
|
|
|
|
} // io
|
|
} // boost</code></pre>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="sect3">
|
|
<h4 id="constructors">Constructors</h4>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">ostream_joiner(ostream_type& output, const Delim& delim);</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="dlist specification">
|
|
<dl>
|
|
<dt class="hdlist1">EFfects</dt>
|
|
<dd>
|
|
<p>Initializes the stored reference to the stream with
|
|
<code>std::addressof(output)</code> and the stored delimiter with <code>delim</code>.</p>
|
|
</dd>
|
|
</dl>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">ostream_joiner(ostream_type& output, Delim&& delim);</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="dlist specification">
|
|
<dl>
|
|
<dt class="hdlist1">EFfects</dt>
|
|
<dd>
|
|
<p>Initializes the stored reference to the stream with
|
|
<code>std::addressof(output)</code> and the stored delimiter with <code>std::move(delim)</code>.</p>
|
|
</dd>
|
|
</dl>
|
|
</div>
|
|
</div>
|
|
<div class="sect3">
|
|
<h4 id="member_functions">Member functions</h4>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">template<class T>
|
|
ostream_joiner& operator=(const T& value);</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="dlist specification">
|
|
<dl>
|
|
<dt class="hdlist1">Effects</dt>
|
|
<dd>
|
|
<p>If the is the first call to this member function, write the stored
|
|
delimiter to the stored stream reference. Writes <code>value</code> to the stored stream
|
|
reference.</p>
|
|
</dd>
|
|
<dt class="hdlist1">Returns</dt>
|
|
<dd>
|
|
<p><code>*this</code>.</p>
|
|
</dd>
|
|
</dl>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">ostream_joiner& operator*() noexcept;</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">ostream_joiner& operator++() noexcept;</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">ostream_joiner& operator++(int) noexcept;</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="dlist specification">
|
|
<dl>
|
|
<dt class="hdlist1">Returns</dt>
|
|
<dd>
|
|
<p><code>*this</code>.</p>
|
|
</dd>
|
|
</dl>
|
|
</div>
|
|
</div>
|
|
<div class="sect3">
|
|
<h4 id="free_functions">Free functions</h4>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">template<class Char, class Traits, class Delim>
|
|
ostream_joiner<decay_t<Delim>, Char, Traits>
|
|
make_ostream_joiner(std::basic_ostream<Char, Traits>& output, Delim&& delim);</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="dlist specification">
|
|
<dl>
|
|
<dt class="hdlist1">Returns</dt>
|
|
<dd>
|
|
<p><code>ostream_joiner<std::decay_t<Delim>, Char, Traits>(output,
|
|
std::forward<Delim>(delim))</code>.</p>
|
|
</dd>
|
|
</dl>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="acknowledgments">Acknowledgments</h3>
|
|
<div class="paragraph">
|
|
<p>Glen Fernandes implemented <code>ostream_joiner</code> and <code>make_ostream_joiner</code>.</p>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="sect1">
|
|
<h2 id="insert_formatted_output_boostioostream_put_hpp">Insert Formatted Output, <boost/io/ostream_put.hpp></h2>
|
|
<div class="sectionbody">
|
|
<div class="sect2">
|
|
<h3 id="description_3">Description</h3>
|
|
<div class="paragraph">
|
|
<p>The header <code><boost/io/ostream_put.hpp></code> provides the function template
|
|
<code>boost::io::ostream_put</code> for formatted output that satisfies the requirements
|
|
of [ostream.formatted.reqmts].</p>
|
|
</div>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="example_3">Example</h3>
|
|
<div class="paragraph">
|
|
<p>The inserter for class template <code>basic_string_view</code> could be implemented as
|
|
follows:</p>
|
|
</div>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">template<class charT, class traits>
|
|
std::basic_ostream<charT, traits>&
|
|
operator<<(std::basic_ostream<charT, traits>& os,
|
|
const basic_string_view<charT, traits>& str)
|
|
{
|
|
return boost::io::ostream_put(os, str.data(), str.size());
|
|
}</code></pre>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="sect2">
|
|
<h3 id="reference_2">Reference</h3>
|
|
<div class="sect3">
|
|
<h4 id="header_synopsis_4">Header Synopsis</h4>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">namespace boost {
|
|
namespace io {
|
|
|
|
template<class charT, class traits>
|
|
std::basic_ostream<charT, traits>&
|
|
ostream_put(std::basic_ostream<charT, traits>& os,
|
|
const charT* data, std::size_t size);
|
|
|
|
} // io
|
|
} // boost</code></pre>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
<div class="sect3">
|
|
<h4 id="free_functions_2">Free functions</h4>
|
|
<div class="listingblock">
|
|
<div class="content">
|
|
<pre class="highlight"><code class="language-cpp" data-lang="cpp">template<class charT, class traits>
|
|
std::basic_ostream<charT, traits>&
|
|
ostream_put(std::basic_ostream<charT, traits>& os,
|
|
const charT* data, std::size_t size);</code></pre>
|
|
</div>
|
|
</div>
|
|
<div class="dlist specification">
|
|
<dl>
|
|
<dt class="hdlist1">Effects</dt>
|
|
<dd>
|
|
<p>Behaves like a formatted inserter (as described in
|
|
[ostream.formatted.reqmts]) of <code>os</code>. Creates a character sequence <code>seq</code> of size
|
|
characters starting at <code>data</code>, each widened using <code>os.widen()</code>
|
|
([basic.ios.members]). Determines padding for <code>seq</code> as described in
|
|
[ostream.formatted.reqmts]. Inserts <code>seq</code> into <code>os</code>. Calls <code>width(0)</code>.</p>
|
|
</dd>
|
|
<dt class="hdlist1">Returns</dt>
|
|
<dd>
|
|
<p><code>os</code>.</p>
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</dd>
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</dl>
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</div>
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</div>
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</div>
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<div class="sect2">
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<h3 id="acknowledgments_2">Acknowledgments</h3>
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|
<div class="paragraph">
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|
<p>Glen Fernandes updated the implementation of the <code>basic_string_ref</code> and
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|
<code>basic_string_view</code> stream insertion operators to write directly to the
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|
<code>basic_streambuf</code> and refactored that functionality into this common utility.</p>
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</div>
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</div>
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</div>
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</div>
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<div class="sect1">
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<h2 id="copyright_and_license">Copyright and License</h2>
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|
<div class="sectionbody">
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|
<div class="ulist">
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|
<ul>
|
|
<li>
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|
<p>Copyright 2002 Daryle Walker</p>
|
|
</li>
|
|
<li>
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|
<p>Copyright 2002, 2006, 2007, 2009, 2010 Beman Dawes</p>
|
|
</li>
|
|
<li>
|
|
<p>Copyright 2019 Glen Joseph Fernandes</p>
|
|
</li>
|
|
</ul>
|
|
</div>
|
|
<div class="paragraph">
|
|
<p>Distributed under the
|
|
<a href="http://www.boost.org/LICENSE_1_0.txt">Boost Software License, Version 1.0</a>.</p>
|
|
</div>
|
|
</div>
|
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</div>
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</div>
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<div id="footer">
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<div id="footer-text">
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Last updated 2021-04-13 16:22:11 UTC
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