NAME

	get9root, unsharp – get path to root of Plan 9 tree

SYNOPSIS

	#include <u.h> #include <libc.h> char* get9root(void) char* unsharp(char *path)

DESCRIPTION

This tree of Plan 9 software is conventionally installed in /home/opt/plan9port but may be installed in other places (for example, users without the ability to write to /usr/local may with to install it in their own home directories). The environment variable $PLAN9 should contain the path to the root. Get9root returns a static pointer to the pathname of root, first checking $PLAN9 and defaulting to /home/opt/plan9port. The lack of a fixed location for the Plan 9 tree makes it difficult to hard-code paths to files. Unsharp replaces a leading #9 in path with the root of the tree. Unsharp also replaces a leading #d with the path to the underlying system’s file descriptor dup device, typically /dev/fd. The string returned from unsharp, if different from path, should be freed with free (see malloc(3)) when no longer needed. As a convention, programs should never unsharp paths obtained from user input.

EXAMPLE

	The plumber(4) uses this code to find unrooted file names included by plumb rules. snprint(buf, sizeof buf, "#9/plumb/%s", name); fd = open(unsharp(buf), OREAD);

SOURCE

	/home/opt/plan9port/src/lib9/get9root.c /home/opt/plan9port/src/lib9/unsharp.c

SEE ALSO

	intro(4)

BUGS

	Get9root could be smarter about finding the tree when $PLAN9 is not set.