1 .TH ACCESS 3
2 .SH NAME
3 access \- determine accessibility of file
4 .SH SYNOPSIS
5 .B #include <u.h>
6 .br
7 .B #include <libc.h>
8 .PP
9 .B
10 int access(char *name, int mode)
11 .SH DESCRIPTION
12 .I Access
13 evaluates the given
14 file
15 .I name
16 for accessibility.
17 If \fImode\fL&4\fR
18 is nonzero,
19 read permission is expected;
20 if \fImode\fL&2\fR,
21 write permission;
22 if \fImode\fL&1\fR,
23 execute permission.
24 If \fImode\fL==0\fR,
25 the file merely need exist.
26 In any case
27 all directories leading to the file
28 must permit searches.
29 Zero is returned if the desired access is permitted,
30 \-1 if not.
31 .PP
32 Only access for open is checked.
33 A file may look executable, but
34 .IR exec (3)
35 will fail unless it is in proper format.
36 .PP
37 The include file
38 .F <libc.h>
39 defines
40 .BR AEXIST =0,
41 .BR AEXEC =1,
42 .BR AWRITE =2,
43 and
44 .BR AREAD =4.
45 .PP
46 .SH SOURCE
47 .B /usr/local/plan9/src/libc/9sys/access.c
48 .SH SEE ALSO
49 .IR stat (3)
50 .SH DIAGNOSTICS
51 Sets
52 .IR errstr .
53 .SH BUGS
54 Since file permissions are checked by the server and group information
55 is not known to the client,
56 .I access
57 must open the file to check permissions.
58 (It calls
59 .IR stat (3)
60 to check simple existence.)