readlink(2)readlink(2)NAMEreadlink - Read the value of a symbolic link
SYNOPSIS
#include <unistd.h>
int readlink(
const char *path,
char *buffer,
size_t buf_size );
The following version of the buf_size argument does not conform to the
XSH specification and is supported only for backward compatibility:
int buf_size
STANDARDS
Interfaces documented on this reference page conform to industry stan‐
dards as follows:
readlink(): XSH4.2, XSH5.0
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
PARAMETERS
Specifies the pathname of the destination file or directory. Points to
the user's buffer. The buffer should be at least as large as the
buf_size parameter. Specifies the size of the buffer.
DESCRIPTION
The readlink() function places the contents of the symbolic link named
by the path parameter in buffer, which has size buf_size.
If the actual length of the symbolic link is greater than buf_size, an
error is returned. The length of a symbolic link will not exceed
PATH_MAX.
[Tru64 UNIX] If the actual length of the symbolic link is less than
buf_size, the string copied into the buffer is null terminated.
For a readlink() function to complete successfully, the calling process
must have search access to the directory containing the link.
RETURN VALUES
Upon successful completion, the readlink() function returns a count of
bytes placed in the buffer (not including any terminating null). If the
readlink() function fails, the buffer is not modified, a value of -1 is
returned, and errno is set to indicate the error.
ERRORS
The readlink() function sets errno to the specified values for the fol‐
lowing conditions:
Search permission is denied on a component of the path prefix of the
path parameter, or read permission is denied on the final component of
the path prefix of the path parameter. The file named by the path
parameter is not a symbolic link. An I/O error occurred while reading
from or writing to the file system. Too many symbolic links were
encountered in resolving path. The length of the path parameter
exceeds PATH_MAX, or a pathname component is longer than NAME_MAX while
_POSIX_NO_TRUNC is in effect. The file named by the path parameter
does not exist or the path parameter points to an empty string. A com‐
ponent of the path prefix of the path parameter is not a directory.
[Tru64 UNIX] The pathname in the symbolic link is longer than
buf_size.
For NFS file access, if the readlink() function fails, errno may also
be set to one of the following values: [Tru64 UNIX] The owner or group
ID is not a value supported by this implementation. [Tru64
UNIX] Indicates a stale NFS file handle. An opened file was deleted by
the server or another client; a client cannot open a file because the
server has unmounted or unexported the remote directory; or the direc‐
tory that contains an opened file was either unmounted or unexported by
the server.
SEE ALSO
Functions: link(2), stat(2), symlink(2), unlink(2)
Standards: standards(5)readlink(2)
