readlink - read value of a symbolic link
int readlink(const char *path, char *buf, size_t bufsiz);
readlink 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. It will truncate the con
tents (to a length of bufsiz characters), in case the
buffer is too small to hold all of the contents.
The call returns the count of characters placed in the
buffer if it succeeds, or a -1 if an error occurs, placing
the error code in errno.
A component of the path prefix is not a directory.
EINVAL bufsiz is not positive.
A pathname, or a component of a pathname, was too
ENOENT The named file does not exist.
EACCES Search permission is denied for a component of the
ELOOP Too many symbolic links were encountered in trans
lating the pathname.
EINVAL The named file is not a symbolic link.
EIO An I/O error occurred while reading from the file
EFAULT buf extends outside the process's allocated address
ENOMEM Insufficient kernel memory was available.
X/OPEN, 4.4BSD (the readlink function call appeared in