| <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>File handling and file I/O</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.1"><link rel="home" href="index.html" title="Websh Reference 3.6.0b5"><link rel="up" href="index.html" title="Websh Reference 3.6.0b5"><link rel="prev" href="context_handling.html" title="Context handling"><link rel="next" href="data_encryption.html" title="Data encryption"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">File handling and file I/O</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="context_handling.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="data_encryption.html">Next</a></td></tr></table><hr></div><div class="section" title="File handling and file I/O"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="file_handling_and_file_IO"></a>File handling and file I/O</h2></div></div></div><div class="section" title="web::include"><div class="titlepage"><div><div><h3 class="title"><a name="web::include"></a><span style="font-family:monospace"><span class="command"><strong>web::include</strong></span></span></h3></div></div></div><p style="width:90%"> |
| |
| </p><div class="cmdsynopsis"><span style="background:#bbbbff"><span style="font-weight:bold"><code class="command">web::include</code></span> <em class="replaceable"><code>fileName</code></em> ?<em class="replaceable"><code>msg</code></em>?</span></div><p style="width:90%"> |
| |
| If the file <tt>fileName</tt> exists, it is sourced (must be a |
| script). Otherwise if the library fileName+"shared lib |
| extension" exists, it is loaded (must be a shared library). |
| Returns 0 on success, 1 otherwise. If an error occurs, an error |
| message is written to <tt>msg</tt>. |
| |
| </p></div><div class="section" title="web::readfile"><div class="titlepage"><div><div><h3 class="title"><a name="web::readfile"></a><span style="font-family:monospace"><span class="command"><strong>web::readfile</strong></span></span></h3></div></div></div><p style="width:90%"> |
| |
| |
| </p><div class="cmdsynopsis"><span style="background:#bbbbff"><span style="font-weight:bold"><code class="command">web::readfile</code></span> <em class="replaceable"><code>file</code></em> <em class="replaceable"><code>varName</code></em> <em class="replaceable"><code>msg</code></em></span></div><p style="width:90%"> |
| |
| Reads <tt>file</tt> and writes it to |
| <tt>varName</tt>. Returns 0 on success, 1 |
| otherwise. If an error occurs, an error message is written to |
| the variable <tt>msg</tt>. |
| |
| </p></div><div class="section" title="web::lockfile and web::unlockfile"><div class="titlepage"><div><div><h3 class="title"><a name="web::lockfile_and_web::unlockfile"></a><span style="font-family:monospace"><span class="command"><strong>web::lockfile</strong></span></span> and <span style="font-family:monospace"><span class="command"><strong>web::unlockfile</strong></span></span></h3></div></div></div><p style="width:90%"> |
| </p><div class="cmdsynopsis"><span style="background:#bbbbff"><span style="font-weight:bold"><code class="command">web::lockfile</code></span> <em class="replaceable"><code>fh</code></em></span></div><p style="width:90%"> |
| </p><div class="cmdsynopsis"><span style="background:#bbbbff"><span style="font-weight:bold"><code class="command">web::unlockfile</code></span> <em class="replaceable"><code>fh</code></em></span></div><p style="width:90%"> |
| |
| Interfaces <code class="function">lockf()</code>. <code class="function">lockf()</code> |
| works best on local filesystems. |
| Please read the documentation of <code class="function">lockf()</code> on your |
| system to learn about the problems and limitations of file locking. |
| Note that |
| <span style="font-family:monospace"><span class="command"><strong>web::lockfile</strong></span></span> also performs a |
| <code class="function">seek()</code> and |
| resets the file cursor to the beginning of the file. |
| |
| <span class="emphasis"><em>Note</em></span> that the file needs to be open for |
| writing. |
| |
| </p></div><div class="section" title="web::truncatefile"><div class="titlepage"><div><div><h3 class="title"><a name="web::truncatefile"></a><span style="font-family:monospace"><span class="command"><strong>web::truncatefile</strong></span></span></h3></div></div></div><p style="width:90%"> |
| |
| |
| </p><div class="cmdsynopsis"><span style="background:#bbbbff"><span style="font-weight:bold"><code class="command">web::truncatefile</code></span> <em class="replaceable"><code>fh</code></em></span></div><p style="width:90%"> |
| |
| Interfaces <code class="function">truncate()</code>. Truncates a file based on |
| the file handle, while Tcl's file commands are based on file |
| names. This is used to truncate a file while holding the lock. |
| |
| </p><div class="example"><a name="id2741455"></a><p class="title"><b>Example 14. <span style="font-family:monospace"><span class="command">web::lockfile</span></span></b></p><div class="example-contents"><pre style="background:#bbffbb ; width:75%" class="programlisting"> |
| set fh [open [web::tempfile] w] |
| web::lockfile $fh |
| puts $fh foo |
| web::unlockfile $fh |
| close $fh </pre></div></div><br class="example-break"></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="context_handling.html">Prev</a> </td><td width="20%" align="center"> </td><td width="40%" align="right"> <a accesskey="n" href="data_encryption.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Context handling </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Data encryption</td></tr></table></div></body></html> |
