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<title>nn_getsockopt(3)</title>
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/*! normalize.css v2.1.2 | MIT License | git.io/normalize */
/* ========================================================================== HTML5 display definitions ========================================================================== */
/** Correct `block` display not defined in IE 8/9. */
article, aside, details, figcaption, figure, footer, header, hgroup, main, nav, section, summary { display: block; }

/** Correct `inline-block` display not defined in IE 8/9. */
audio, canvas, video { display: inline-block; }

/** Prevent modern browsers from displaying `audio` without controls. Remove excess height in iOS 5 devices. */
audio:not([controls]) { display: none; height: 0; }

/** Address `[hidden]` styling not present in IE 8/9. Hide the `template` element in IE, Safari, and Firefox < 22. */
[hidden], template { display: none; }

script { display: none !important; }

/* ========================================================================== Base ========================================================================== */
/** 1. Set default font family to sans-serif. 2. Prevent iOS text size adjust after orientation change, without disabling user zoom. */
html { font-family: sans-serif; /* 1 */ -ms-text-size-adjust: 100%; /* 2 */ -webkit-text-size-adjust: 100%; /* 2 */ }

/** Remove default margin. */
body { margin: 0; }

/* ========================================================================== Links ========================================================================== */
/** Remove the gray background color from active links in IE 10. */
a { background: transparent; }

/** Address `outline` inconsistency between Chrome and other browsers. */
a:focus { outline: thin dotted; }

/** Improve readability when focused and also mouse hovered in all browsers. */
a:active, a:hover { outline: 0; }

/* ========================================================================== Typography ========================================================================== */
/** Address variable `h1` font-size and margin within `section` and `article` contexts in Firefox 4+, Safari 5, and Chrome. */
h1 { font-size: 2em; margin: 0.67em 0; }

/** Address styling not present in IE 8/9, Safari 5, and Chrome. */
abbr[title] { border-bottom: 1px dotted; }

/** Address style set to `bolder` in Firefox 4+, Safari 5, and Chrome. */
b, strong { font-weight: bold; }

/** Address styling not present in Safari 5 and Chrome. */
dfn { font-style: italic; }

/** Address differences between Firefox and other browsers. */
hr { -moz-box-sizing: content-box; box-sizing: content-box; height: 0; }

/** Address styling not present in IE 8/9. */
mark { background: #ff0; color: #000; }

/** Correct font family set oddly in Safari 5 and Chrome. */
code, kbd, pre, samp { font-family: monospace, serif; font-size: 1em; }

/** Improve readability of pre-formatted text in all browsers. */
pre { white-space: pre-wrap; }

/** Set consistent quote types. */
q { quotes: "\201C" "\201D" "\2018" "\2019"; }

/** Address inconsistent and variable font size in all browsers. */
small { font-size: 80%; }

/** Prevent `sub` and `sup` affecting `line-height` in all browsers. */
sub, sup { font-size: 75%; line-height: 0; position: relative; vertical-align: baseline; }

sup { top: -0.5em; }

sub { bottom: -0.25em; }

/* ========================================================================== Embedded content ========================================================================== */
/** Remove border when inside `a` element in IE 8/9. */
img { border: 0; }

/** Correct overflow displayed oddly in IE 9. */
svg:not(:root) { overflow: hidden; }

/* ========================================================================== Figures ========================================================================== */
/** Address margin not present in IE 8/9 and Safari 5. */
figure { margin: 0; }

/* ========================================================================== Forms ========================================================================== */
/** Define consistent border, margin, and padding. */
fieldset { border: 1px solid #c0c0c0; margin: 0 2px; padding: 0.35em 0.625em 0.75em; }

/** 1. Correct `color` not being inherited in IE 8/9. 2. Remove padding so people aren't caught out if they zero out fieldsets. */
legend { border: 0; /* 1 */ padding: 0; /* 2 */ }

/** 1. Correct font family not being inherited in all browsers. 2. Correct font size not being inherited in all browsers. 3. Address margins set differently in Firefox 4+, Safari 5, and Chrome. */
button, input, select, textarea { font-family: inherit; /* 1 */ font-size: 100%; /* 2 */ margin: 0; /* 3 */ }

/** Address Firefox 4+ setting `line-height` on `input` using `!important` in the UA stylesheet. */
button, input { line-height: normal; }

/** Address inconsistent `text-transform` inheritance for `button` and `select`. All other form control elements do not inherit `text-transform` values. Correct `button` style inheritance in Chrome, Safari 5+, and IE 8+. Correct `select` style inheritance in Firefox 4+ and Opera. */
button, select { text-transform: none; }

/** 1. Avoid the WebKit bug in Android 4.0.* where (2) destroys native `audio` and `video` controls. 2. Correct inability to style clickable `input` types in iOS. 3. Improve usability and consistency of cursor style between image-type `input` and others. */
button, html input[type="button"], input[type="reset"], input[type="submit"] { -webkit-appearance: button; /* 2 */ cursor: pointer; /* 3 */ }

/** Re-set default cursor for disabled elements. */
button[disabled], html input[disabled] { cursor: default; }

/** 1. Address box sizing set to `content-box` in IE 8/9. 2. Remove excess padding in IE 8/9. */
input[type="checkbox"], input[type="radio"] { box-sizing: border-box; /* 1 */ padding: 0; /* 2 */ }

/** 1. Address `appearance` set to `searchfield` in Safari 5 and Chrome. 2. Address `box-sizing` set to `border-box` in Safari 5 and Chrome (include `-moz` to future-proof). */
input[type="search"] { -webkit-appearance: textfield; /* 1 */ -moz-box-sizing: content-box; -webkit-box-sizing: content-box; /* 2 */ box-sizing: content-box; }

/** Remove inner padding and search cancel button in Safari 5 and Chrome on OS X. */
input[type="search"]::-webkit-search-cancel-button, input[type="search"]::-webkit-search-decoration { -webkit-appearance: none; }

/** Remove inner padding and border in Firefox 4+. */
button::-moz-focus-inner, input::-moz-focus-inner { border: 0; padding: 0; }

/** 1. Remove default vertical scrollbar in IE 8/9. 2. Improve readability and alignment in all browsers. */
textarea { overflow: auto; /* 1 */ vertical-align: top; /* 2 */ }

/* ========================================================================== Tables ========================================================================== */
/** Remove most spacing between table cells. */
table { border-collapse: collapse; border-spacing: 0; }

meta.foundation-mq-small { font-family: "only screen and (min-width: 768px)"; width: 768px; }

meta.foundation-mq-medium { font-family: "only screen and (min-width:1280px)"; width: 1280px; }

meta.foundation-mq-large { font-family: "only screen and (min-width:1440px)"; width: 1440px; }

*, *:before, *:after { -moz-box-sizing: border-box; -webkit-box-sizing: border-box; box-sizing: border-box; }

html, body { font-size: 100%; }

body { background: #fff; color: #222; padding: 0; margin: 0; font-family: "Helvetica Neue", "Helvetica", Helvetica, Arial, sans-serif; font-weight: normal; font-style: normal; line-height: 1; position: relative; cursor: auto; }

a:hover { cursor: pointer; }

img, object, embed { max-width: 100%; height: auto; }

object, embed { height: 100%; }

img { -ms-interpolation-mode: bicubic; }

#map_canvas img, #map_canvas embed, #map_canvas object, .map_canvas img, .map_canvas embed, .map_canvas object { max-width: none !important; }

.left { float: left !important; }

.right { float: right !important; }

.text-left { text-align: left !important; }

.text-right { text-align: right !important; }

.text-center { text-align: center !important; }

.text-justify { text-align: justify !important; }

.hide { display: none; }

.antialiased, body { -webkit-font-smoothing: antialiased; }

img { display: inline-block; vertical-align: middle; }

textarea { height: auto; min-height: 50px; }

select { width: 100%; }

object, svg { display: inline-block; vertical-align: middle; }

.center { margin-left: auto; margin-right: auto; }

.spread { width: 100%; }

p.lead, .paragraph.lead > p, #preamble > .sectionbody > .paragraph:first-of-type p { font-size: 1.21875em; line-height: 1.6; }

.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: 1.4; color: #003b6b; font-weight: 300; margin-top: 0.2em; margin-bottom: 0.5em; }

/* Typography resets */
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; }

/* Default Link Styles */
a { color: #00579e; text-decoration: none; line-height: inherit; }
a:hover, a:focus { color: #333; }
a img { border: none; }

/* Default paragraph styles */
p { font-family: Arial, sans-serif; font-weight: normal; font-size: 1em; line-height: 1.6; margin-bottom: 0.75em; text-rendering: optimizeLegibility; }
p aside { font-size: 0.875em; line-height: 1.35; font-style: italic; }

/* Default header styles */
h1, h2, h3, #toctitle, .sidebarblock > .content > .title, h4, h5, h6 { font-family: Arial, sans-serif; font-weight: normal; font-style: normal; color: #7B2D00; text-rendering: optimizeLegibility; margin-top: 0.5em; margin-bottom: 0.5em; line-height: 1.2125em; }
h1 small, h2 small, h3 small, #toctitle small, .sidebarblock > .content > .title small, h4 small, h5 small, h6 small { font-size: 60%; color: #ff6b15; line-height: 0; }

h1 { font-size: 2.125em; }

h2 { font-size: 1.6875em; }

h3, #toctitle, .sidebarblock > .content > .title { font-size: 1.375em; }

h4 { font-size: 1.125em; }

h5 { font-size: 1.125em; }

h6 { font-size: 1em; }

hr { border: solid #ddd; border-width: 1px 0 0; clear: both; margin: 1.25em 0 1.1875em; height: 0; }

/* Helpful Typography Defaults */
em, i { font-style: italic; line-height: inherit; }

strong, b { font-weight: bold; line-height: inherit; }

small { font-size: 60%; line-height: inherit; }

code { font-family: Consolas, "Liberation Mono", Courier, monospace; font-weight: bold; color: #003426; }

/* Lists */
ul, ol, dl { font-size: 1em; line-height: 1.6; margin-bottom: 0.75em; list-style-position: outside; font-family: Arial, sans-serif; }

ul, ol { margin-left: 1.5em; }
ul.no-bullet, ol.no-bullet { margin-left: 1.5em; }

/* Unordered Lists */
ul li ul, ul li ol { margin-left: 1.25em; margin-bottom: 0; font-size: 1em; /* Override nested font-size change */ }
ul.square li ul, ul.circle li ul, ul.disc li ul { list-style: inherit; }
ul.square { list-style-type: square; }
ul.circle { list-style-type: circle; }
ul.disc { list-style-type: disc; }
ul.no-bullet { list-style: none; }

/* Ordered Lists */
ol li ul, ol li ol { margin-left: 1.25em; margin-bottom: 0; }

/* Definition Lists */
dl dt { margin-bottom: 0.3em; font-weight: bold; }
dl dd { margin-bottom: 0.75em; }

/* Abbreviations */
abbr, acronym { text-transform: uppercase; font-size: 90%; color: black; border-bottom: 1px dotted #ddd; cursor: help; }

abbr { text-transform: none; }

/* Blockquotes */
blockquote { margin: 0 0 0.75em; padding: 0.5625em 1.25em 0 1.1875em; border-left: 1px solid #ddd; }
blockquote cite { display: block; font-size: 0.8125em; color: #e15200; }
blockquote cite:before { content: "\2014 \0020"; }
blockquote cite a, blockquote cite a:visited { color: #e15200; }

blockquote, blockquote p { line-height: 1.6; color: #333; }

/* Microformats */
.vcard { display: inline-block; margin: 0 0 1.25em 0; border: 1px solid #ddd; padding: 0.625em 0.75em; }
.vcard li { margin: 0; display: block; }
.vcard .fn { font-weight: bold; font-size: 0.9375em; }

.vevent .summary { font-weight: bold; }
.vevent abbr { cursor: auto; text-decoration: none; font-weight: bold; border: none; padding: 0 0.0625em; }

@media only screen and (min-width: 768px) { h1, h2, h3, #toctitle, .sidebarblock > .content > .title, h4, h5, h6 { line-height: 1.4; }
  h1 { font-size: 2.75em; }
  h2 { font-size: 2.3125em; }
  h3, #toctitle, .sidebarblock > .content > .title { font-size: 1.6875em; }
  h4 { font-size: 1.4375em; } }
/* Tables */
table { background: #fff; margin-bottom: 1.25em; border: solid 1px #d8d8ce; }
table thead, table tfoot { background: -webkit-linear-gradient(top, #add386, #90b66a); font-weight: bold; }
table thead tr th, table thead tr td, table tfoot tr th, table tfoot tr td { padding: 0.5em 0.625em 0.625em; font-size: inherit; color: #fff; text-align: left; }
table tr th, table tr td { padding: 0.5625em 0.625em; font-size: inherit; color: #6d6e71; }
table tr.even, table tr.alt, table tr:nth-of-type(even) { background: #edf2f2; }
table thead tr th, table tfoot tr th, table tbody tr td, table tr td, table tfoot tr td { display: table-cell; line-height: 1.4; }

body { tab-size: 4; }

h1, h2, h3, #toctitle, .sidebarblock > .content > .title, h4, h5, h6 { line-height: 1.4; }

a:hover, a:focus { text-decoration: underline; }

.clearfix:before, .clearfix:after, .float-group:before, .float-group:after { content: " "; display: table; }
.clearfix:after, .float-group:after { clear: both; }

*:not(pre) > code { font-size: inherit; font-style: normal !important; letter-spacing: 0; padding: 3px 2px 1px 2px; background-color: #eee; border: 1px solid #ddd; -webkit-border-radius: 0; border-radius: 0; line-height: inherit; }

pre, pre > code { line-height: 1.6; color: black; font-family: Consolas, "Liberation Mono", Courier, monospace; font-weight: normal; }

.keyseq { color: #333333; }

kbd { font-family: Consolas, "Liberation Mono", Courier, monospace; display: inline-block; color: black; font-size: 0.65em; line-height: 1.45; background-color: #f7f7f7; border: 1px solid #ccc; -webkit-border-radius: 3px; border-radius: 3px; -moz-box-shadow: 0 1px 0 rgba(0, 0, 0, 0.2), 0 0 0 0.1em white inset; -webkit-box-shadow: 0 1px 0 rgba(0, 0, 0, 0.2), 0 0 0 0.1em white inset; box-shadow: 0 1px 0 rgba(0, 0, 0, 0.2), 0 0 0 0.1em white inset; margin: 0 0.15em; padding: 0.2em 0.5em; vertical-align: middle; position: relative; top: -0.1em; white-space: nowrap; }

.keyseq kbd:first-child { margin-left: 0; }

.keyseq kbd:last-child { margin-right: 0; }

.menuseq, .menu { color: black; }

b.button:before, b.button:after { position: relative; top: -1px; font-weight: normal; }

b.button:before { content: "["; padding: 0 3px 0 2px; }

b.button:after { content: "]"; padding: 0 2px 0 3px; }

#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: 1.5em; padding-right: 1.5em; }
#header:before, #header:after, #content:before, #content:after, #footnotes:before, #footnotes:after, #footer:before, #footer:after { content: " "; display: table; }
#header:after, #content:after, #footnotes:after, #footer:after { clear: both; }

#content { margin-top: 1.25em; }

#content:before { content: none; }

#header > h1:first-child { color: #7B2D00; margin-top: 2.25rem; margin-bottom: 0; }
#header > h1:first-child + #toc { margin-top: 8px; border-top: 1px solid #ddd; }
#header > h1:only-child, body.toc2 #header > h1:nth-last-child(2) { border-bottom: 1px solid #ddd; padding-bottom: 8px; }
#header .details { border-bottom: 1px solid #ddd; line-height: 1.45; padding-top: 0.25em; padding-bottom: 0.25em; padding-left: 0.25em; color: #e15200; display: -ms-flexbox; display: -webkit-flex; display: flex; -ms-flex-flow: row wrap; -webkit-flex-flow: row wrap; flex-flow: row wrap; }
#header .details span:first-child { margin-left: -0.125em; }
#header .details span.email a { color: #333; }
#header .details br { display: none; }
#header .details br + span:before { content: "\00a0\2013\00a0"; }
#header .details br + span.author:before { content: "\00a0\22c5\00a0"; color: #333; }
#header .details br + span#revremark:before { content: "\00a0|\00a0"; }
#header #revnumber { text-transform: capitalize; }
#header #revnumber:after { content: "\00a0"; }

#content > h1:first-child:not([class]) { color: #7B2D00; border-bottom: 1px solid #ddd; padding-bottom: 8px; margin-top: 0; padding-top: 1rem; margin-bottom: 1.25rem; }

#toc { border-bottom: 0 solid #ddd; padding-bottom: 0.5em; }
#toc > ul { margin-left: 0.125em; }
#toc ul.sectlevel0 > li > a { font-style: italic; }
#toc ul.sectlevel0 ul.sectlevel1 { margin: 0.5em 0; }
#toc ul { font-family: Arial, sans-serif; list-style-type: none; }
#toc li { line-height: 1.3334; margin-top: 0.3334em; }
#toc a { text-decoration: none; }
#toc a:active { text-decoration: underline; }

#toctitle { color: #003b6b; font-size: 1.2em; }

@media only screen and (min-width: 768px) { #toctitle { font-size: 1.375em; }
  body.toc2 { padding-left: 15em; padding-right: 0; }
  #toc.toc2 { margin-top: 0 !important; background-color: #fff; position: fixed; width: 15em; left: 0; top: 0; border-right: 1px solid #ddd; border-top-width: 0 !important; border-bottom-width: 0 !important; z-index: 1000; padding: 1.25em 1em; height: 100%; overflow: auto; }
  #toc.toc2 #toctitle { margin-top: 0; margin-bottom: 0.8rem; font-size: 1.2em; }
  #toc.toc2 > ul { font-size: 0.9em; margin-bottom: 0; }
  #toc.toc2 ul ul { margin-left: 0; padding-left: 1em; }
  #toc.toc2 ul.sectlevel0 ul.sectlevel1 { padding-left: 0; margin-top: 0.5em; margin-bottom: 0.5em; }
  body.toc2.toc-right { padding-left: 0; padding-right: 15em; }
  body.toc2.toc-right #toc.toc2 { border-right-width: 0; border-left: 1px solid #ddd; left: auto; right: 0; } }
@media only screen and (min-width: 1280px) { body.toc2 { padding-left: 20em; padding-right: 0; }
  #toc.toc2 { width: 20em; }
  #toc.toc2 #toctitle { font-size: 1.375em; }
  #toc.toc2 > ul { font-size: 0.95em; }
  #toc.toc2 ul ul { padding-left: 1.25em; }
  body.toc2.toc-right { padding-left: 0; padding-right: 20em; } }
#content #toc { border-style: solid; border-width: 1px; border-color: #e6e6e6; margin-bottom: 1.25em; padding: 1.25em; background: #fff; -webkit-border-radius: 0; border-radius: 0; }
#content #toc > :first-child { margin-top: 0; }
#content #toc > :last-child { margin-bottom: 0; }

#footer { max-width: 100%; background-color: none; padding: 1.25em; }

#footer-text { color: black; line-height: 1.44; }

.sect1 { padding-bottom: 0.625em; }

@media only screen and (min-width: 768px) { .sect1 { padding-bottom: 1.25em; } }
.sect1 + .sect1 { border-top: 0 solid #ddd; }

#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: normal; }
#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: 0.85em; display: block; padding-top: 0.1em; }
#content h1:hover > a.anchor, #content h1 > a.anchor:hover, h2:hover > a.anchor, h2 > a.anchor:hover, h3:hover > a.anchor, #toctitle:hover > a.anchor, .sidebarblock > .content > .title:hover > a.anchor, h3 > a.anchor:hover, #toctitle > a.anchor:hover, .sidebarblock > .content > .title > a.anchor:hover, h4:hover > a.anchor, h4 > a.anchor:hover, h5:hover > a.anchor, h5 > a.anchor:hover, h6:hover > a.anchor, h6 > a.anchor:hover { visibility: visible; }
#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: #7B2D00; text-decoration: none; }
#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: #622400; }

.audioblock, .imageblock, .literalblock, .listingblock, .stemblock, .videoblock { margin-bottom: 1.25em; }

.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 { text-rendering: optimizeLegibility; text-align: left; }

table.tableblock > caption.title { white-space: nowrap; overflow: visible; max-width: 0; }

.paragraph.lead > p, #preamble > .sectionbody > .paragraph:first-of-type p { color: #7B2D00; }

table.tableblock #preamble > .sectionbody > .paragraph:first-of-type p { font-size: inherit; }

.admonitionblock > table { border-collapse: separate; border: 0; background: none; width: 100%; }
.admonitionblock > table td.icon { text-align: center; width: 80px; }
.admonitionblock > table td.icon img { max-width: none; }
.admonitionblock > table td.icon .title { font-weight: bold; font-family: Arial, sans-serif; text-transform: uppercase; }
.admonitionblock > table td.content { padding-left: 1.125em; padding-right: 1.25em; border-left: 1px solid #ddd; color: #e15200; }
.admonitionblock > table td.content > :last-child > :last-child { margin-bottom: 0; }

.exampleblock > .content { border-style: solid; border-width: 1px; border-color: #e6e6e6; margin-bottom: 1.25em; padding: 1.25em; background: #fff; -webkit-border-radius: 0; border-radius: 0; }
.exampleblock > .content > :first-child { margin-top: 0; }
.exampleblock > .content > :last-child { margin-bottom: 0; }

.sidebarblock { border-style: solid; border-width: 1px; border-color: #e6e6e6; margin-bottom: 1.25em; padding: 1.25em; background: #fff; -webkit-border-radius: 0; border-radius: 0; }
.sidebarblock > :first-child { margin-top: 0; }
.sidebarblock > :last-child { margin-bottom: 0; }
.sidebarblock > .content > .title { color: #003b6b; margin-top: 0; }

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</head>
<body class="manpage toc2 toc-left">
<div id="header">
<h1>nn_getsockopt(3) Manual Page</h1>
<div id="toc" class="toc2">
<div id="toctitle">Table of Contents</div>
<ul class="sectlevel1">
<li><a href="#_synopsis">SYNOPSIS</a></li>
<li><a href="#_description">DESCRIPTION</a></li>
<li><a href="#_return_value">RETURN VALUE</a></li>
<li><a href="#_errors">ERRORS</a></li>
<li><a href="#_example">EXAMPLE</a></li>
<li><a href="#_see_also">SEE ALSO</a></li>
<li><a href="#_authors">AUTHORS</a></li>
</ul>
</div>
<h2>NAME</h2>
<div class="sectionbody">
<p>nn_getsockopt - retrieve a socket option</p>
</div>
</div>
<div id="content">
<div class="sect1">
<h2 id="_synopsis">SYNOPSIS</h2>
<div class="sectionbody">
<div class="paragraph">
<p><strong>#include &lt;nanomsg/nn.h&gt;</strong></p>
</div>
<div class="paragraph">
<p><strong>int nn_getsockopt (int <em>s</em>, int <em>level</em>, int <em>option</em>, void <em>*optval</em>, size_t <em>*optvallen</em>);</strong></p>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_description">DESCRIPTION</h2>
<div class="sectionbody">
<div class="paragraph">
<p>Retrieves the value for the <em>option</em>. The <em>level</em> argument specifies
the protocol level at which the option resides. For generic socket-level options
use <em>NN_SOL_SOCKET</em> level. For socket-type-specific options use socket type
for <em>level</em> argument (e.g. <em>NN_SUB</em>). For transport-specific options use ID of
the transport as the <em>level</em> argument (e.g. <em>NN_TCP</em>).</p>
</div>
<div class="paragraph">
<p>The value is stored in the buffer pointed to by <em>optval</em> argument. Size of the
buffer is specified by the <em>optvallen</em> argument. If the size of the option is
greater than size of the buffer, the value will be silently truncated.
Otherwise, the <em>optvallen</em> will be modified to indicate the actual length of
the option.</p>
</div>
<div class="paragraph">
<p><em>&lt;nanomsg/nn.h&gt;</em> header defines generic socket-level options
(<em>NN_SOL_SOCKET</em> level). The options are as follows:</p>
</div>
<div class="dlist">
<dl>
<dt class="hdlist1"><strong>NN_DOMAIN</strong></dt>
<dd>
<p>Returns the domain constant as it was passed to <em>nn_socket()</em>.</p>
</dd>
<dt class="hdlist1"><strong>NN_PROTOCOL</strong></dt>
<dd>
<p>Returns the protocol constant as it was passed to <em>nn_socket()</em>.</p>
</dd>
<dt class="hdlist1"><strong>NN_LINGER</strong></dt>
<dd>
<p>Specifies how long the socket should try to send pending outbound messages
after <em>nn_close()</em> have been called, in milliseconds. Negative value means
infinite linger. The type of the option is int. Default value
is 1000 (1 second).</p>
</dd>
<dt class="hdlist1"><strong>NN_SNDBUF</strong></dt>
<dd>
<p>Size of the send buffer, in bytes. To prevent blocking for messages larger
than the buffer, exactly one message may be buffered in addition to the data
in the send buffer. The type of this option is int. Default value is 128kB.</p>
</dd>
<dt class="hdlist1"><strong>NN_RCVBUF</strong></dt>
<dd>
<p>Size of the receive buffer, in bytes. To prevent blocking for messages
larger than the buffer, exactly one message may be buffered in addition
to the data in the receive buffer. The type of this option is int. Default
value is 128kB.</p>
</dd>
<dt class="hdlist1"><strong>NN_RCVMAXSIZE</strong></dt>
<dd>
<p>Maximum message size that can be received, in bytes. Negative value means
that the received size is limited only by available addressable memory. The
type of this option is int. Default is 1024kB.</p>
</dd>
<dt class="hdlist1"><strong>NN_SNDTIMEO</strong></dt>
<dd>
<p>The timeout for send operation on the socket, in milliseconds. If message
cannot be sent within the specified timeout, EAGAIN error is returned.
Negative value means infinite timeout. The type of the option is int.
Default value is -1.</p>
</dd>
<dt class="hdlist1"><strong>NN_RCVTIMEO</strong></dt>
<dd>
<p>The timeout for recv operation on the socket, in milliseconds. If message
cannot be received within the specified timeout, EAGAIN error is returned.
Negative value means infinite timeout. The type of the option is int.
Default value is -1.</p>
</dd>
<dt class="hdlist1"><strong>NN_RECONNECT_IVL</strong></dt>
<dd>
<p>For connection-based transports such as TCP, this option specifies how
long to wait, in milliseconds, when connection is broken before trying
to re-establish it. Note that actual reconnect interval may be randomised
to some extent to prevent severe reconnection storms. The type of the option
is int. Default value is 100 (0.1 second).</p>
</dd>
<dt class="hdlist1"><strong>NN_RECONNECT_IVL_MAX</strong></dt>
<dd>
<p>This option is to be used only in addition to <em>NN_RECONNECT_IVL</em> option.
It specifies maximum reconnection interval. On each reconnect attempt,
the previous interval is doubled until <em>NN_RECONNECT_IVL_MAX</em> is reached.
Value of zero means that no exponential backoff is performed and reconnect
interval is based only on <em>NN_RECONNECT_IVL</em>. If <em>NN_RECONNECT_IVL_MAX</em> is
less than <em>NN_RECONNECT_IVL</em>, it is ignored. The type of the option is int.
Default value is 0.</p>
</dd>
<dt class="hdlist1"><strong>NN_SNDPRIO</strong></dt>
<dd>
<p>Retrieves outbound priority currently set on the socket. This
option has no effect on socket types that send messages to all the peers.
However, if the socket type sends each message to a single peer
(or a limited set of peers), peers with high priority take precedence
over peers with low priority. The type of the option is int. Highest
priority is 1, lowest priority is 16. Default value is 8.</p>
</dd>
<dt class="hdlist1"><strong>NN_RCVPRIO</strong></dt>
<dd>
<p>Sets inbound priority for endpoints subsequently added to the socket. This
option has no effect on socket types that are not able to receive messages.
When receiving a message, messages from peer with higher priority are
received before messages from peer with lower priority. The type of the
option is int. Highest priority is 1, lowest priority is 16. Default value
is 8.</p>
</dd>
<dt class="hdlist1"><strong>NN_IPV4ONLY</strong></dt>
<dd>
<p>If set to 1, only IPv4 addresses are used. If set to 0, both IPv4 and IPv6
addresses are used. The type of the option is int. Default value is 1.</p>
</dd>
<dt class="hdlist1"><strong>NN_SNDFD</strong></dt>
<dd>
<p>Retrieves a file descriptor that is readable when a message can be sent
to the socket. The descriptor should be used only for polling and never
read from or written to. The type of the option is same as the type of
file descriptor on the platform. That is, int on POSIX-complaint platforms
and SOCKET on Windows. The descriptor becomes invalid and should not be
used any more once the socket is closed. This socket option is not available
for unidirectional recv-only socket types.</p>
</dd>
<dt class="hdlist1"><strong>NN_RCVFD</strong></dt>
<dd>
<p>Retrieves a file descriptor that is readable when a message can be received
from the socket. The descriptor should be used only for polling and never
read from or written to. The type of the option is same as the type of
file descriptor on the platform. That is, int on POSIX-complaint platforms
and SOCKET on Windows. The descriptor becomes invalid and should not be
used any more once the socket is closed. This socket option is not available
for unidirectional send-only socket types.</p>
</dd>
<dt class="hdlist1"><strong>NN_SOCKET_NAME</strong></dt>
<dd>
<p>Socket name for error reporting and statistics. The type of the option
is string. Default value is "N" where N is socket integer.
<strong>This option is experimental, see <a href="nn_env.7.html">nn_env(7)</a> for details</strong></p>
</dd>
</dl>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_return_value">RETURN VALUE</h2>
<div class="sectionbody">
<div class="paragraph">
<p>If the function succeeds zero is returned. Otherwise, -1 is
returned and <em>errno</em> is set to to one of the values defined below.</p>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_errors">ERRORS</h2>
<div class="sectionbody">
<div class="dlist">
<dl>
<dt class="hdlist1"><strong>EBADF</strong></dt>
<dd>
<p>The provided socket is invalid.</p>
</dd>
<dt class="hdlist1"><strong>ENOPROTOOPT</strong></dt>
<dd>
<p>The option is unknown at the level indicated.</p>
</dd>
<dt class="hdlist1"><strong>ETERM</strong></dt>
<dd>
<p>The library is terminating.</p>
</dd>
</dl>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_example">EXAMPLE</h2>
<div class="sectionbody">
<div class="listingblock">
<div class="content">
<pre>int linger;
size_t sz = sizeof (linger);
nn_getsockopt (s, NN_SOL_SOCKET, NN_LINGER, &amp;linger, &amp;sz);</pre>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_see_also">SEE ALSO</h2>
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<p><a href="nn_socket.3.html">nn_socket(3)</a>
<a href="nn_setsockopt.3.html">nn_setsockopt(3)</a>
<a href="nanomsg.7.html">nanomsg(7)</a></p>
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<h2 id="_authors">AUTHORS</h2>
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<p><a href="mailto:sustrik@250bpm.com">Martin Sustrik</a></p>
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nanomsg 0.8-beta-21-g327a29b-dirty<br>
Last updated 2016-04-15 11:01:53 PDT
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