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228 lines
6.9 KiB
HTML
228 lines
6.9 KiB
HTML
4 years ago
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<!-- Copyright (C) 1988-2019 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with the
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Invariant Sections being "Free Software" and "Free Software Needs
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Free Documentation", with the Front-Cover Texts being "A GNU Manual,"
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and with the Back-Cover Texts as in (a) below.
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(a) The FSF's Back-Cover Text is: "You are free to copy and modify
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this GNU Manual. Buying copies from GNU Press supports the FSF in
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developing GNU and promoting software freedom." -->
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<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>open (Debugging with GDB)</title>
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<meta name="description" content="open (Debugging with GDB)">
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<meta name="keywords" content="open (Debugging with GDB)">
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<meta name="resource-type" content="document">
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<meta name="distribution" content="global">
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<meta name="Generator" content="makeinfo">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link href="index.html#Top" rel="start" title="Top">
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<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="List-of-Supported-Calls.html#List-of-Supported-Calls" rel="up" title="List of Supported Calls">
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<link href="close.html#close" rel="next" title="close">
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<link href="List-of-Supported-Calls.html#List-of-Supported-Calls" rel="prev" title="List of Supported Calls">
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<style type="text/css">
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a.summary-letter {text-decoration: none}
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blockquote.indentedblock {margin-right: 0em}
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blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
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blockquote.smallquotation {font-size: smaller}
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div.display {margin-left: 3.2em}
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div.example {margin-left: 3.2em}
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div.lisp {margin-left: 3.2em}
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div.smalldisplay {margin-left: 3.2em}
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div.smallexample {margin-left: 3.2em}
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div.smalllisp {margin-left: 3.2em}
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kbd {font-style: oblique}
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pre.display {font-family: inherit}
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pre.format {font-family: inherit}
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pre.menu-comment {font-family: serif}
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pre.menu-preformatted {font-family: serif}
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pre.smalldisplay {font-family: inherit; font-size: smaller}
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pre.smallexample {font-size: smaller}
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pre.smallformat {font-family: inherit; font-size: smaller}
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pre.smalllisp {font-size: smaller}
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span.nolinebreak {white-space: nowrap}
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span.roman {font-family: initial; font-weight: normal}
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span.sansserif {font-family: sans-serif; font-weight: normal}
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ul.no-bullet {list-style: none}
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-->
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</style>
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</head>
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<body lang="en">
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<a name="open"></a>
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<div class="header">
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<p>
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Next: <a href="close.html#close" accesskey="n" rel="next">close</a>, Up: <a href="List-of-Supported-Calls.html#List-of-Supported-Calls" accesskey="u" rel="up">List of Supported Calls</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="open-1"></a>
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<h4 class="unnumberedsubsubsec">open</h4>
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<a name="index-open_002c-file_002di_002fo-system-call"></a>
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<dl compact="compact">
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<dt>Synopsis:</dt>
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<dd><div class="smallexample">
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<pre class="smallexample">int open(const char *pathname, int flags);
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int open(const char *pathname, int flags, mode_t mode);
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</pre></div>
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</dd>
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<dt>Request:</dt>
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<dd><p>‘<samp>Fopen,<var>pathptr</var>/<var>len</var>,<var>flags</var>,<var>mode</var></samp>’
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</p>
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<p><var>flags</var> is the bitwise <code>OR</code> of the following values:
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</p>
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<dl compact="compact">
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<dt><code>O_CREAT</code></dt>
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<dd><p>If the file does not exist it will be created. The host
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rules apply as far as file ownership and time stamps
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are concerned.
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</p>
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</dd>
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<dt><code>O_EXCL</code></dt>
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<dd><p>When used with <code>O_CREAT</code>, if the file already exists it is
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an error and open() fails.
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</p>
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</dd>
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<dt><code>O_TRUNC</code></dt>
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<dd><p>If the file already exists and the open mode allows
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writing (<code>O_RDWR</code> or <code>O_WRONLY</code> is given) it will be
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truncated to zero length.
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</p>
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</dd>
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<dt><code>O_APPEND</code></dt>
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<dd><p>The file is opened in append mode.
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</p>
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</dd>
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<dt><code>O_RDONLY</code></dt>
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<dd><p>The file is opened for reading only.
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</p>
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</dd>
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<dt><code>O_WRONLY</code></dt>
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<dd><p>The file is opened for writing only.
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</p>
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</dd>
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<dt><code>O_RDWR</code></dt>
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<dd><p>The file is opened for reading and writing.
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</p></dd>
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</dl>
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<p>Other bits are silently ignored.
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</p>
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<p><var>mode</var> is the bitwise <code>OR</code> of the following values:
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</p>
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<dl compact="compact">
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<dt><code>S_IRUSR</code></dt>
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<dd><p>User has read permission.
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</p>
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</dd>
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<dt><code>S_IWUSR</code></dt>
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<dd><p>User has write permission.
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</p>
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</dd>
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<dt><code>S_IRGRP</code></dt>
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<dd><p>Group has read permission.
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</p>
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</dd>
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<dt><code>S_IWGRP</code></dt>
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<dd><p>Group has write permission.
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</p>
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</dd>
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<dt><code>S_IROTH</code></dt>
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<dd><p>Others have read permission.
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</p>
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</dd>
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<dt><code>S_IWOTH</code></dt>
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<dd><p>Others have write permission.
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</p></dd>
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</dl>
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<p>Other bits are silently ignored.
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</p>
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</dd>
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<dt>Return value:</dt>
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<dd><p><code>open</code> returns the new file descriptor or -1 if an error
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occurred.
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</p>
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</dd>
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<dt>Errors:</dt>
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<dd>
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<dl compact="compact">
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<dt><code>EEXIST</code></dt>
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<dd><p><var>pathname</var> already exists and <code>O_CREAT</code> and <code>O_EXCL</code> were used.
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</p>
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</dd>
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<dt><code>EISDIR</code></dt>
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<dd><p><var>pathname</var> refers to a directory.
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</p>
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</dd>
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<dt><code>EACCES</code></dt>
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<dd><p>The requested access is not allowed.
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</p>
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</dd>
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<dt><code>ENAMETOOLONG</code></dt>
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<dd><p><var>pathname</var> was too long.
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</p>
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</dd>
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<dt><code>ENOENT</code></dt>
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<dd><p>A directory component in <var>pathname</var> does not exist.
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</p>
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</dd>
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<dt><code>ENODEV</code></dt>
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<dd><p><var>pathname</var> refers to a device, pipe, named pipe or socket.
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</p>
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</dd>
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<dt><code>EROFS</code></dt>
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<dd><p><var>pathname</var> refers to a file on a read-only filesystem and
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write access was requested.
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</p>
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</dd>
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<dt><code>EFAULT</code></dt>
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<dd><p><var>pathname</var> is an invalid pointer value.
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</p>
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</dd>
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<dt><code>ENOSPC</code></dt>
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<dd><p>No space on device to create the file.
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</p>
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</dd>
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<dt><code>EMFILE</code></dt>
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<dd><p>The process already has the maximum number of files open.
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</p>
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</dd>
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<dt><code>ENFILE</code></dt>
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<dd><p>The limit on the total number of files open on the system
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has been reached.
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</p>
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</dd>
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<dt><code>EINTR</code></dt>
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<dd><p>The call was interrupted by the user.
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</p></dd>
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</dl>
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</dd>
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</dl>
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<hr>
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<div class="header">
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<p>
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Next: <a href="close.html#close" accesskey="n" rel="next">close</a>, Up: <a href="List-of-Supported-Calls.html#List-of-Supported-Calls" accesskey="u" rel="up">List of Supported Calls</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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</body>
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</html>
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