READLINK(2) BSD System Calls Manual READLINK(2)NAMEreadlink — read value of a symbolic link
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
ssize_t
readlink(const char * restrict path, char * restrict buf, size_t bufsiz);
DESCRIPTIONreadlink() places the contents of the symbolic link path in the buffer
buf, which has size bufsiz. readlink() does not append a NUL character
to buf.
RETURN VALUES
The call returns the count of characters placed in the buffer if it suc‐
ceeds, or a -1 if an error occurs, placing the error code in the global
variable errno.
EXAMPLES
A typical use is illustrated in the following piece of code which reads
the contents of a symbolic link named /symbolic/link and stores them as
null-terminated string:
#include <limits.h>
#include <unistd.h>
char buf[PATH_MAX];
ssize_t len;
if ((len = readlink("/symbolic/link", buf, sizeof(buf)-1)) == -1)
error handling;
buf[len] = '\0';
ERRORSreadlink() will fail if:
[ENOTDIR] A component of the path prefix is not a directory.
[ENAMETOOLONG] A component of a pathname exceeded {NAME_MAX} charac‐
ters, or an entire path name exceeded {PATH_MAX} char‐
acters.
[ENOENT] The named file does not exist.
[EACCES] Search permission is denied for a component of the
path prefix.
[ELOOP] Too many symbolic links were encountered in translat‐
ing the pathname.
[EINVAL] The named file is not a symbolic link.
[EIO] An I/O error occurred while reading from the file sys‐
tem.
[EFAULT] buf extends outside the process's allocated address
space.
SEE ALSOlstat(2), stat(2), symlink(2), symlink(7)STANDARDS
The readlink() function conforms to IEEE Std 1003.1-2001 (“POSIX.1”).
HISTORY
The readlink() function appeared in 4.2BSD. The type returned was
changed from int to ssize_t in NetBSD 2.1.
BSD May 11, 2004 BSD