typedef enum { ... } SilcSFTPFSMemoryPerm;

    Memory filesystem permission definition.  These enumerations can
    be used to set the permission mask for directories and files.
    The permissions behave in POSIX style.

    typedef enum {
      SILC_SFTP_FS_PERM_READ    = 0x0001,    /* Reading allowed */
      SILC_SFTP_FS_PERM_WRITE   = 0x0002,    /* Writing allowed */
      SILC_SFTP_FS_PERM_EXEC    = 0x0004,    /* Execution allowed */
    } SilcSFTPFSMemoryPerm;