Module Dbm
module Dbm: sig end
Interface to the NDBM database.
type t
The type of file descriptors opened on NDBM databases.
type open_flag =
| |
Dbm_rdonly |
| |
Dbm_wronly |
| |
Dbm_rdwr |
| |
Dbm_create |
(* | Flags for opening a database (see Dbm.opendbm ). | *) |
exception Dbm_error of string
Raised by the following functions when an error is encountered.
val opendbm : string -> open_flag list -> int -> t
Open a descriptor on an NDBM database. The first argument is
the name of the database (without the .dir
and .pag
suffixes).
The second argument is a list of flags: Dbm_rdonly
opens
the database for reading only, Dbm_wronly
for writing only,
Dbm_rdwr
for reading and writing; Dbm_create
causes the
database to be created if it does not already exist.
The third argument is the permissions to give to the database
files, if the database is created.
val close : t -> unit
Close the given descriptor.
val find : t -> string -> string
find db key
returns the data associated with the given
key
in the database opened for the descriptor db
.
Raise Not_found
if the key
has no associated data.
val add : t -> string -> string -> unit
add db key data
inserts the pair (key
, data
) in
the database db
. If the database already contains data
associated with key
, raise Dbm_error "Entry already exists"
.
val replace : t -> string -> string -> unit
replace db key data
inserts the pair (key
, data
) in
the database db
. If the database already contains data
associated with key
, that data is discarded and silently
replaced by the new data
.
val remove : t -> string -> unit
remove db key data
removes the data associated with key
in db
. If key
has no associated data, raise
Dbm_error "dbm_delete"
.
val firstkey : t -> string
val nextkey : t -> string
Enumerate all keys in the given database, in an unspecified order.
firstkey db
returns the first key, and repeated calls
to nextkey db
return the remaining keys. Not_found
is raised
when all keys have been enumerated.
val iter : (string -> string -> 'a) -> t -> unit
iter f db
applies f
to each (key
, data
) pair in
the database db
. f
receives key
as first argument
and data
as second argument.