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| <tr><td width=20><td><b>DIRREAD(3)</b><td align=right><b>DIRREAD(3)</b> |
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| <p><font size=+1><b>NAME </b></font><br> |
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| dirread, dirreadall – read directory<br> |
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| <p><font size=+1><b>SYNOPSIS </b></font><br> |
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| <tt><font size=+1>#include <u.h><br> |
| #include <libc.h> |
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| <tt><font size=+1>long dirread(int fd, Dir **buf) |
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| </font></tt> |
| <tt><font size=+1>long dirreadall(int fd, Dir **buf) |
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| </font></tt> |
| <tt><font size=+1>#define STATMAX 65535U |
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| </font></tt> |
| <tt><font size=+1>#define DIRMAX (sizeof(Dir)+STATMAX)<br> |
| </font></tt> |
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| <p><font size=+1><b>DESCRIPTION </b></font><br> |
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| The data returned by a <a href="../man3/read.html"><i>read</i>(3)</a> on a directory is a set of complete |
| directory entries in a machine-independent format, exactly equivalent |
| to the result of a <a href="../man3/stat.html"><i>stat</i>(3)</a> on each file or subdirectory in the |
| directory. <i>Dirread</i> decodes the directory entries into a machine-dependent |
| form. It reads from <i>fd</i> and unpacks the data |
| into an array of <tt><font size=+1>Dir</font></tt> structures whose address is returned in <tt><font size=+1>*buf</font></tt> |
| (see <a href="../man3/stat.html"><i>stat</i>(3)</a> for the layout of a <tt><font size=+1>Dir</font></tt>). The array is allocated |
| with <a href="../man3/malloc.html"><i>malloc</i>(3)</a> each time <i>dirread</i> is called. |
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| <i>Dirreadall</i> is like <i>dirread</i>, but reads in the entire directory; |
| by contrast, <i>dirread</i> steps through a directory one <a href="../man3/read.html"><i>read</i>(3)</a> at |
| a time. |
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| Directory entries have variable length. A successful <i>read</i> of a |
| directory always returns an integral number of complete directory |
| entries; <i>dirread</i> always returns complete <tt><font size=+1>Dir</font></tt> structures. See <i>read</i>(9p) |
| for more information. |
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| The constant <tt><font size=+1>STATMAX</font></tt> is the maximum size that a directory entry |
| can occupy. The constant <tt><font size=+1>DIRMAX</font></tt> is an upper limit on the size |
| necessary to hold a <tt><font size=+1>Dir</font></tt> structure and all the associated data. |
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| <i>Dirread</i> and <i>dirreadall</i> return the number of <tt><font size=+1>Dir</font></tt> structures filled |
| in <tt><font size=+1>buf</font></tt>. The file offset is advanced by the number of bytes actually |
| read.<br> |
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| <p><font size=+1><b>SOURCE </b></font><br> |
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| <tt><font size=+1>/usr/local/plan9/src/lib9/dirread.c<br> |
| </font></tt> |
| </table> |
| <p><font size=+1><b>SEE ALSO </b></font><br> |
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| <a href="../man3/intro.html"><i>intro</i>(3)</a>, <a href="../man3/open.html"><i>open</i>(3)</a>, <a href="../man3/read.html"><i>read</i>(3)</a><br> |
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| </table> |
| <p><font size=+1><b>DIAGNOSTICS </b></font><br> |
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| <i>Dirread</i> and <i>Dirreadall</i> return zero for end of file and a negative |
| value for error. In either case, <tt><font size=+1>*buf</font></tt> is set to <tt><font size=+1>nil</font></tt> so the pointer |
| can always be freed with impunity. |
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| These functions set <i>errstr</i>.<br> |
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