diff options
Diffstat (limited to 'ref/api/args.html')
| -rw-r--r-- | ref/api/args.html | 455 |
1 files changed, 455 insertions, 0 deletions
diff --git a/ref/api/args.html b/ref/api/args.html new file mode 100644 index 00000000..f2fb8c8d --- /dev/null +++ b/ref/api/args.html @@ -0,0 +1,455 @@ +<!DOCTYPE HTML> +<html lang="en" class="light sidebar-visible" dir="ltr"> + <head> + <!-- Book generated using mdBook --> + <meta charset="UTF-8"> + <title>Arguments Parser - NNG Reference Manual (DRAFT)</title> + + + <!-- Custom HTML head --> + + <meta name="description" content=""> + <meta name="viewport" content="width=device-width, initial-scale=1"> + <meta name="theme-color" content="#ffffff"> + + <link rel="icon" href="../favicon.svg"> + <link rel="shortcut icon" href="../favicon.png"> + <link rel="stylesheet" href="../css/variables.css"> + <link rel="stylesheet" href="../css/general.css"> + <link rel="stylesheet" href="../css/chrome.css"> + <link rel="stylesheet" href="../css/print.css" media="print"> + + <!-- Fonts --> + <link rel="stylesheet" href="../FontAwesome/css/font-awesome.css"> + <link rel="stylesheet" href="../fonts/fonts.css"> + + <!-- Highlight.js Stylesheets --> + <link rel="stylesheet" href="../highlight.css"> + <link rel="stylesheet" href="../tomorrow-night.css"> + <link rel="stylesheet" href="../ayu-highlight.css"> + + <!-- Custom theme stylesheets --> + <link rel="stylesheet" href="../theme/pagetoc.css"> + + + <!-- Provide site root to javascript --> + <script> + var path_to_root = "../"; + var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "navy" : "light"; + </script> + <!-- Start loading toc.js asap --> + <script src="../toc.js"></script> + </head> + <body> + <div id="body-container"> + <!-- Work around some values being stored in localStorage wrapped in quotes --> + <script> + try { + var theme = localStorage.getItem('mdbook-theme'); + var sidebar = localStorage.getItem('mdbook-sidebar'); + + if (theme.startsWith('"') && theme.endsWith('"')) { + localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1)); + } + + if (sidebar.startsWith('"') && sidebar.endsWith('"')) { + localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1)); + } + } catch (e) { } + </script> + + <!-- Set the theme before any content is loaded, prevents flash --> + <script> + var theme; + try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { } + if (theme === null || theme === undefined) { theme = default_theme; } + const html = document.documentElement; + html.classList.remove('light') + html.classList.add(theme); + html.classList.add("js"); + </script> + + <input type="checkbox" id="sidebar-toggle-anchor" class="hidden"> + + <!-- Hide / unhide sidebar before it is displayed --> + <script> + var sidebar = null; + var sidebar_toggle = document.getElementById("sidebar-toggle-anchor"); + if (document.body.clientWidth >= 1080) { + try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { } + sidebar = sidebar || 'visible'; + } else { + sidebar = 'hidden'; + } + sidebar_toggle.checked = sidebar === 'visible'; + html.classList.remove('sidebar-visible'); + html.classList.add("sidebar-" + sidebar); + </script> + + <nav id="sidebar" class="sidebar" aria-label="Table of contents"> + <!-- populated by js --> + <mdbook-sidebar-scrollbox class="sidebar-scrollbox"></mdbook-sidebar-scrollbox> + <noscript> + <iframe class="sidebar-iframe-outer" src="../toc.html"></iframe> + </noscript> + <div id="sidebar-resize-handle" class="sidebar-resize-handle"> + <div class="sidebar-resize-indicator"></div> + </div> + </nav> + + <div id="page-wrapper" class="page-wrapper"> + + <div class="page"> + <div id="menu-bar-hover-placeholder"></div> + <div id="menu-bar" class="menu-bar sticky"> + <div class="left-buttons"> + <label id="sidebar-toggle" class="icon-button" for="sidebar-toggle-anchor" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar"> + <i class="fa fa-bars"></i> + </label> + <button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list"> + <i class="fa fa-paint-brush"></i> + </button> + <ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu"> + <li role="none"><button role="menuitem" class="theme" id="light">Light</button></li> + <li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li> + <li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li> + <li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li> + <li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li> + </ul> + <button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar"> + <i class="fa fa-search"></i> + </button> + </div> + + <h1 class="menu-title">NNG Reference Manual (DRAFT)</h1> + + <div class="right-buttons"> + <a href="../print.html" title="Print this book" aria-label="Print this book"> + <i id="print-button" class="fa fa-print"></i> + </a> + + </div> + </div> + + <div id="search-wrapper" class="hidden"> + <form id="searchbar-outer" class="searchbar-outer"> + <input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header"> + </form> + <div id="searchresults-outer" class="searchresults-outer hidden"> + <div id="searchresults-header" class="searchresults-header"></div> + <ul id="searchresults"> + </ul> + </div> + </div> + + <!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM --> + <script> + document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible'); + document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible'); + Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) { + link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1); + }); + </script> + + <div id="content" class="content"> + <main> + <style> +.mdbook-alerts { + padding: 8px 16px; + margin-bottom: 16px; + border-left: 0.25em solid var(--mdbook-alerts-color); +} + +.mdbook-alerts > *:first-child { + margin-top: 0; +} + +.mdbook-alerts > *:last-child { + margin-bottom: 0; +} + +.mdbook-alerts-title { + display: flex; + font-weight: 600; + align-items: center; + line-height: 1; + color: var(--mdbook-alerts-color); + text-transform: capitalize; +} + +.mdbook-alerts-icon { + display: inline-block; + width: 1em; + height: 1em; + margin-right: 0.2em; + background-color: currentColor; + -webkit-mask: no-repeat center / 100%; + mask: no-repeat center / 100%; + -webkit-mask-image: var(--mdbook-alerts-icon); + mask-image: var(--mdbook-alerts-icon); +} + +.mdbook-alerts-note { + --mdbook-alerts-color: rgb(9, 105, 218); + /* https://icon-sets.iconify.design/material-symbols/info-outline-rounded/ */ + --mdbook-alerts-icon: url('data:image/svg+xml,%3Csvg xmlns="http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg" width="24" height="24" viewBox="0 0 24 24"%3E%3Cpath fill="currentColor" d="M12 17q.425 0 .713-.288T13 16v-4q0-.425-.288-.712T12 11q-.425 0-.712.288T11 12v4q0 .425.288.713T12 17m0-8q.425 0 .713-.288T13 8q0-.425-.288-.712T12 7q-.425 0-.712.288T11 8q0 .425.288.713T12 9m0 13q-2.075 0-3.9-.788t-3.175-2.137q-1.35-1.35-2.137-3.175T2 12q0-2.075.788-3.9t2.137-3.175q1.35-1.35 3.175-2.137T12 2q2.075 0 3.9.788t3.175 2.137q1.35 1.35 2.138 3.175T22 12q0 2.075-.788 3.9t-2.137 3.175q-1.35 1.35-3.175 2.138T12 22m0-2q3.35 0 5.675-2.325T20 12q0-3.35-2.325-5.675T12 4Q8.65 4 6.325 6.325T4 12q0 3.35 2.325 5.675T12 20m0-8"%2F%3E%3C%2Fsvg%3E'); +} + +.mdbook-alerts-tip { + --mdbook-alerts-color: rgb(26, 127, 55); + /* https://icon-sets.iconify.design/material-symbols/lightbulb-outline-rounded/ */ + --mdbook-alerts-icon: url('data:image/svg+xml,%3Csvg xmlns="http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg" width="24" height="24" viewBox="0 0 24 24"%3E%3Cpath fill="currentColor" d="M12 22q-.825 0-1.412-.587T10 20h4q0 .825-.587 1.413T12 22m-3-3q-.425 0-.712-.288T8 18q0-.425.288-.712T9 17h6q.425 0 .713.288T16 18q0 .425-.288.713T15 19zm-.75-3q-1.725-1.025-2.738-2.75T4.5 9.5q0-3.125 2.188-5.312T12 2q3.125 0 5.313 2.188T19.5 9.5q0 2.025-1.012 3.75T15.75 16zm.6-2h6.3q1.125-.8 1.738-1.975T17.5 9.5q0-2.3-1.6-3.9T12 4Q9.7 4 8.1 5.6T6.5 9.5q0 1.35.613 2.525T8.85 14M12 14"%2F%3E%3C%2Fsvg%3E'); +} + +.mdbook-alerts-important { + --mdbook-alerts-color: rgb(130, 80, 223); + /* https://icon-sets.iconify.design/material-symbols/chat-info-outline-rounded/ */ + --mdbook-alerts-icon: url('data:image/svg+xml,%3Csvg xmlns="http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg" width="24" height="24" viewBox="0 0 24 24"%3E%3Cpath fill="currentColor" d="M12 7q.425 0 .713-.288T13 6q0-.425-.288-.712T12 5q-.425 0-.712.288T11 6q0 .425.288.713T12 7m0 8q.425 0 .713-.288T13 14v-4q0-.425-.288-.712T12 9q-.425 0-.712.288T11 10v4q0 .425.288.713T12 15m-6 3l-2.3 2.3q-.475.475-1.088.213T2 19.575V4q0-.825.588-1.412T4 2h16q.825 0 1.413.588T22 4v12q0 .825-.587 1.413T20 18zm-.85-2H20V4H4v13.125zM4 16V4z"%2F%3E%3C%2Fsvg%3E'); +} + +.mdbook-alerts-warning { + --mdbook-alerts-color: rgb(154, 103, 0); + /* https://icon-sets.iconify.design/material-symbols/warning-outline-rounded/ */ + --mdbook-alerts-icon: url('data:image/svg+xml,%3Csvg xmlns="http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg" width="24" height="24" viewBox="0 0 24 24"%3E%3Cpath fill="currentColor" d="M2.725 21q-.275 0-.5-.137t-.35-.363q-.125-.225-.137-.488t.137-.512l9.25-16q.15-.25.388-.375T12 3q.25 0 .488.125t.387.375l9.25 16q.15.25.138.513t-.138.487q-.125.225-.35.363t-.5.137zm1.725-2h15.1L12 6zM12 18q.425 0 .713-.288T13 17q0-.425-.288-.712T12 16q-.425 0-.712.288T11 17q0 .425.288.713T12 18m0-3q.425 0 .713-.288T13 14v-3q0-.425-.288-.712T12 10q-.425 0-.712.288T11 11v3q0 .425.288.713T12 15m0-2.5"%2F%3E%3C%2Fsvg%3E'); +} + +.mdbook-alerts-caution { + --mdbook-alerts-color: rgb(207, 34, 46); + /* https://icon-sets.iconify.design/material-symbols/brightness-alert-outline-rounded/ */ + --mdbook-alerts-icon: url('data:image/svg+xml,%3Csvg xmlns="http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg" width="24" height="24" viewBox="0 0 24 24"%3E%3Cpath fill="currentColor" d="M12 17q.425 0 .713-.288T13 16q0-.425-.288-.712T12 15q-.425 0-.712.288T11 16q0 .425.288.713T12 17m0-4q.425 0 .713-.288T13 12V8q0-.425-.288-.712T12 7q-.425 0-.712.288T11 8v4q0 .425.288.713T12 13m-3.35 7H6q-.825 0-1.412-.587T4 18v-2.65L2.075 13.4q-.275-.3-.425-.662T1.5 12q0-.375.15-.737t.425-.663L4 8.65V6q0-.825.588-1.412T6 4h2.65l1.95-1.925q.3-.275.663-.425T12 1.5q.375 0 .738.15t.662.425L15.35 4H18q.825 0 1.413.588T20 6v2.65l1.925 1.95q.275.3.425.663t.15.737q0 .375-.15.738t-.425.662L20 15.35V18q0 .825-.587 1.413T18 20h-2.65l-1.95 1.925q-.3.275-.662.425T12 22.5q-.375 0-.737-.15t-.663-.425zm.85-2l2.5 2.5l2.5-2.5H18v-3.5l2.5-2.5L18 9.5V6h-3.5L12 3.5L9.5 6H6v3.5L3.5 12L6 14.5V18zm2.5-6"%2F%3E%3C%2Fsvg%3E'); +} + +</style> +<h1 id="command-arguments"><a class="header" href="#command-arguments">Command Arguments</a></h1> +<p>Some NNG utilities need to parse command line options, +and for this purpose a header library is supplied.</p> +<p>To make use of this, the header <code><nng/args.h></code> must be included.</p> +<div class="mdbook-alerts mdbook-alerts-tip"> +<p class="mdbook-alerts-title"> + <span class="mdbook-alerts-icon"></span> + tip +</p> +<p>The functionality described here is entirely contained in the +<code>nng/args.h</code> header file, and may be used without previously +initializing the library with <a href="/api/init.html#initialization"><code>nng_init</code></a>, and may even be used +in programs that are not linked against the NNG library.</p> +</div> +<h2 id="parse-command-line-arguments"><a class="header" href="#parse-command-line-arguments">Parse Command Line Arguments</a></h2> +<pre><code class="language-c">typedef struct nng_arg_spec { + const char *a_name; // Long style name (may be NULL for short only) + int a_short; // Short option (no clustering!) + int a_val; // Value stored on a good parse (>0) + bool a_arg; // Option takes an argument if true +} nng_optspec; + +#define NNG_ARG_END (-1) +#define NNG_ARG_INVAL (-2) +#define NNG_ARG_AMBIG (-3) +#define NNG_ARG_MISSING (-4) + +int nng_args_parse(int argc, char *const *argv, + const nng_optspec *spec, int *val, char **arg, int *idx); +</code></pre> +<p>The <a name="a001"></a><code>nng_args_parse</code> function is intended to facilitate parsing +<a name="a002"></a>command-line arguments. +This function exists largely to stand in for <a name="a003"></a><code>getopt</code> from POSIX systems, +but it is available on all platforms, and it includes some capabilities missing from <code>getopt</code>.</p> +<p>The function parses arguments from +<code>main</code><sup><a name="to-footnote-1"><a href="#footnote-1">1</a></a></sup> +(using <em>argc</em> and <em>argv</em>), +starting at the index referenced by <em>idx</em>. +(New invocations typically set the value pointed to by <em>idx</em> to 1.)</p> +<p>Options are parsed as specified by <em>spec</em> (see <a href="#argument-specification">Argument Specification</a>.) +The value of the parsed option will be stored at the address indicated by +<em>val</em>, and the value of <em>idx</em> will be incremented to reflect the next +option to parse.</p> +<div class="mdbook-alerts mdbook-alerts-tip"> +<p class="mdbook-alerts-title"> + <span class="mdbook-alerts-icon"></span> + tip +</p> +<p>For using this to parse command-line like strings that do not include +the command name itself, set the value referenced by <em>idx</em> to zero instead of one.</p> +</div> +<p>If the option had an argument, a pointer to that is returned at the address +referenced by <em>arg</em>.</p> +<p>This function should be called repeatedly, until it returns either -1 +(indicating the end of options is reached) or a non-zero error code is +returned.</p> +<p>This function may return the following errors:</p> +<ul> +<li>[<code>NNG_ARG_AMBIGU</code>]: Parsed option matches more than one specification.</li> +<li>[<code>NNG_ARG_MISSING</code>]: Option requires an argument, but one is not present.</li> +<li>[<code>NNG_ARG_INVAL</code>]: An invalid (unknown) argument is present in <em>argv</em>.</li> +</ul> +<h3 id="option-specification"><a class="header" href="#option-specification">Option Specification</a></h3> +<p>The calling program must first create an array of <a name="a004"></a><code>nng_arg_spec</code> structures +describing the options to be supported. +This structure has the following members:</p> +<ul> +<li> +<p><code>a_name</code>:</p> +<p>The long style name for the option, such as “verbose”. +This will be parsed as a <a href="#long-options">long option</a> on the command line when it is prefixed with two dashes. +It may be <code>NULL</code> if only a <a href="#short-options">short option</a> is to be supported.</p> +</li> +<li> +<p><code>a_short</code>:</p> +<p>This is a single letter (at present only ASCII letters are supported). +These options appear as just a single letter, and are prefixed with a single dash on the command line. +The use of a slash in lieu of the dash is <em>not</em> supported, in order to avoid confusion with path name arguments. +This value may be set to 0 if no <a href="#short-options">short option</a> is needed.</p> +</li> +<li> +<p><code>o_val</code>:</p> +<p>This is a numeric value that is unique to this option. +This value is assigned by the application program, and must be non-zero for a valid option. +If this is zero, then it indicates the end of the specifications, and the +rest of this structure is ignored. +The value will be returned to the caller in <em>val</em> by <code>nng_args_parse</code> when +this option is parsed from the command line.</p> +</li> +<li> +<p><code>a_arg</code>:</p> +<p>This value should be set to <code>true</code> if the option should take an argument.</p> +</li> +</ul> +<h3 id="long-options"><a class="header" href="#long-options">Long Options</a></h3> +<p>Long options are parsed from the <em>argv</em> array, and are indicated when +the element being scanned starts with two dashes. +For example, the “verbose” option would be specified as <code>--verbose</code> on +the command line. +If a long option takes an argument, it can either immediately follow +the option as the next element in <em>argv</em>, or it can be appended to +the option, separated from the option by an equals sign (<code>=</code>) or a +colon (<code>:</code>).</p> +<h3 id="short-options"><a class="header" href="#short-options">Short Options</a></h3> +<p>Short options appear by themselves in an <em>argv</em> element, prefixed by a dash (<code>-</code>). +If the short option takes an argument, it can either be appended in the +same element of <em>argv</em>, or may appear in the next <em>argv</em> element.</p> +<div class="mdbook-alerts mdbook-alerts-note"> +<p class="mdbook-alerts-title"> + <span class="mdbook-alerts-icon"></span> + note +</p> +<p>Option clustering, where multiple options can be crammed together in +a single <em>argv</em> element, is not supported by this function (yet).</p> +</div> +<h3 id="prefix-matching"><a class="header" href="#prefix-matching">Prefix Matching</a></h3> +<p>When using long options, the parser will match if it is equal to a prefix +of the <code>a_name</code> member of a option specification, provided that it do so +unambiguously (meaning it must not match any other option specification.)</p> +<h2 id="example"><a class="header" href="#example">Example</a></h2> +<p>The following program fragment demonstrates this function.</p> +<pre><code class="language-c"> enum { OPT_LOGFILE, OPT_VERBOSE }; + char *logfile; // options to be set + bool verbose; + + static nng_arg_spec specs[] = { + { + .a_name = "logfile", + .a_short = 'D', + .a_val = OPT_LOGFILE, + .a_arg = true, + }, { + .a_name = "verbose", + .a_short = 'V', + .a_val = OPT_VERBOSE, + .a_arg = false, + }, { + .a_val = 0; // Terminate array + } + }; + + for (int idx = 1;;) { + int rv, opt; + char *arg; + rv = nng_args_parse(argc, argv, specs, &opt, &arg, &idx); + if (rv != 0) { + break; + } + switch (opt) { + case OPT_LOGFILE: + logfile = arg; + break; + case OPT_VERBOSE: + verbose = true; + break; + } + } + if (rv != NNG_ARG_END) { + switch (rv) { + case NNG_ARG_AMBIG: + printf("Options error: ambiguous option\n"); + break; + case NNG_ARG_MISSING: + printf("Options error: required option argument missing\n"); + break; + case NNG_ARG_INVAL: + printf("Options error: unknown option present\n"); + break; + } + exit(1); + } +</code></pre> +<!-- Symbol cross reference --> +<!-- Macros --> +<!-- Protocols --> +<!-- Transports --> +<!-- Concept index --> +<p><hr/> +<p><a name="footnote-1"><a href="#to-footnote-1">1</a></a>: Parsing argument strings from other sources can be done as well, +although usually then <em>idx</em> will be initialized to zero.</p> + + </main> + + <nav class="nav-wrapper" aria-label="Page navigation"> + <!-- Mobile navigation buttons --> + <a rel="prev" href="../api/id_map.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left"> + <i class="fa fa-angle-left"></i> + </a> + + <a rel="next prefetch" href="../proto/index.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right"> + <i class="fa fa-angle-right"></i> + </a> + + <div style="clear: both"></div> + </nav> + </div> + </div> + + <nav class="nav-wide-wrapper" aria-label="Page navigation"> + <a rel="prev" href="../api/id_map.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left"> + <i class="fa fa-angle-left"></i> + </a> + + <a rel="next prefetch" href="../proto/index.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right"> + <i class="fa fa-angle-right"></i> + </a> + </nav> + + </div> + + + + + <script> + window.playground_copyable = true; + </script> + + + <script src="../elasticlunr.min.js"></script> + <script src="../mark.min.js"></script> + <script src="../searcher.js"></script> + + <script src="../clipboard.min.js"></script> + <script src="../highlight.js"></script> + <script src="../book.js"></script> + + <!-- Custom JS scripts --> + <script src="../theme/pagetoc.js"></script> + + + </div> + </body> +</html> |