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| <title>get9root(3) - Plan 9 from User Space</title> |
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| <tr><td width=20><td><b>GET9ROOT(3)</b><td align=right><b>GET9ROOT(3)</b> |
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| <p><font size=+1><b>NAME </b></font><br> |
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| get9root, unsharp – get path to root of Plan 9 tree<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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| </font></tt> |
| <tt><font size=+1>char* get9root(void) |
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| </font></tt> |
| <tt><font size=+1>char* unsharp(char *path)<br> |
| </font></tt> |
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| <p><font size=+1><b>DESCRIPTION </b></font><br> |
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| This tree of Plan 9 software is conventionally installed in <tt><font size=+1>/usr/local/plan9</font></tt> |
| but may be installed in other places (for example, users without |
| the ability to write to <tt><font size=+1>/usr/local</font></tt> may with to install it in their |
| own home directories). The environment variable <tt><font size=+1>$PLAN9</font></tt> should |
| contain the path to the root. <i>Get9root |
| </i>returns a static pointer to the pathname of root, first checking |
| <tt><font size=+1>$PLAN9</font></tt> and defaulting to <tt><font size=+1>/usr/local/plan9</font></tt>. |
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| The lack of a fixed location for the Plan 9 tree makes it difficult |
| to hard-code paths to files. <i>Unsharp</i> replaces a leading <tt><font size=+1>#9</font></tt> in |
| <i>path</i> with the root of the tree. <i>Unsharp</i> also replaces a leading |
| <tt><font size=+1>#d</font></tt> with the path to the underlying system’s file descriptor dup |
| device, typically <tt><font size=+1>/dev/fd</font></tt>. The string returned from <i>unsharp</i>, if |
| different from <i>path</i>, should be freed with <i>free</i> (see <a href="../man3/malloc.html"><i>malloc</i>(3)</a>) |
| when no longer needed. |
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| As a convention, programs should never <i>unsharp</i> paths obtained |
| from user input.<br> |
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| </table> |
| <p><font size=+1><b>EXAMPLE </b></font><br> |
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| The <a href="../man4/plumber.html"><i>plumber</i>(4)</a> uses this code to find unrooted file names included |
| by plumb rules.<br> |
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| <tt><font size=+1>snprint(buf, sizeof buf, "#9/plumb/%s", name);<br> |
| fd = open(unsharp(buf), OREAD);<br> |
| </font></tt> |
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| </table> |
| <p><font size=+1><b>SOURCE </b></font><br> |
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| <tt><font size=+1>/usr/local/plan9/src/lib9/getns.c<br> |
| </font></tt> |
| </table> |
| <p><font size=+1><b>SEE ALSO </b></font><br> |
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| <a href="../man4/intro.html"><i>intro</i>(4)</a><br> |
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| </table> |
| <p><font size=+1><b>BUGS </b></font><br> |
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| <i>Get9root</i> could be smarter about finding the tree when <tt><font size=+1>$PLAN9</font></tt> is |
| not set.<br> |
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