ACCESS(2) ACCESS(2)
NAME
access - determine accessibility of file
SYNOPSIS
#include <u.h>
#include <libc.h>
int access(char *name, int mode)
DESCRIPTION
Access evaluates the given file name for accessibility. If
mode&4 is nonzero, read permission is expected; if mode&2,
write permission; if mode&1, execute permission. If
mode==0, the file merely need exist. In any case all direc-
tories leading to the file must permit searches. Zero is
returned if the desired access is permitted, -1 if not.
Only access bits are checked. A file may look executable,
but exec(2) will fail unless it is in proper format.
The include file defines AEXIST=0, AEXEC=1, AWRITE=2, and
AREAD=4.
SOURCE
/sys/src/libc/9sys/access.c
SEE ALSO
stat(2)
DIAGNOSTICS
Sets errstr.
BUGS
Since file permissions are checked by the server and group
information is not known to the client, access must open the
file to check permissions. (It calls stat(2) to check sim-
ple existence.) Besides giving misleading information about
the writability of directories, this is as expensive as the
open that access is often intended to avoid.
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