readlink - read value of a symbolic link
int readlink(const char *path, char *buf, int bufsiz)
Readlink places the contents of the symbolic link name in the buffer buf,
which has size bufsiz. The contents of the link are not null terminated
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 the
global variable errno.
Readlink will fail and the file mode will be unchanged if:
[ENOTDIR] A component of the path prefix is not a directory.
[ENAMETOOLONG] The path name exceeds PATH_MAX characters.
[ENOENT] The named file does not exist.
[EACCES] Search permission is denied for a component of the path
[ELOOP] Too many symbolic links were encountered in translating
the pathname. (Minix-vmd)
[EINVAL] The named file is not a symbolic link.
[EIO] An I/O error occurred while reading from the file system.
[EFAULT] Buf extends outside the process's allocated address space.
stat(2), lstat(2), symlink(2).