|| The dynlink library: dynamic loading and linking of object files
The dynlink library supports type-safe dynamic loading and linking
of bytecode object files (.cmo and .cma files) in a running
bytecode program. Type safety is ensured by limiting the set of
modules from the running program that the loaded object file can
access, and checking that the running program and the loaded object
file have been compiled against the same interfaces for these modules.
Programs that use the dynlink library simply need to link
dynlink.cma with their object files and other libraries.
Dynamic linking is available only to bytecode programs compiled with
|| Module Dynlink: dynamic loading of bytecode object files
val init : unit -> unit
Initialize the library. Must be called before
val loadfile : string -> unit
Load the given bytecode object file and link it.
All toplevel expressions in the loaded compilation unit
are evaluated. No facilities are provided to
access value names defined by the unit. Therefore, the unit
must register itself its entry points with the main program,
e.g. by modifying tables of functions.
val loadfile_private : string -> unit
loadfile, except that the module loaded is not
made available to other modules dynamically loaded afterwards.
val add_interfaces : units:string list -> paths:string list -> unit
add_interfaces units path grants dynamically-linked object
files access to the compilation units named in list
The interfaces (
.cmi files) for these units are searched in
path (a list of directory names). Initially, dynamically-linked
object files do not have access to any of the compilation
units composing the running program, not even the standard library.
add_available_units (see below) must be
called to grant access to some of the units.
val add_available_units : (string * Digest.t) list -> unit
add_interfaces, but instead of searching
to find the unit interfaces, uses the interface digests given
for each unit. This way, the
.cmi interface files need not be
available at run-time. The digests can be extracted from
files using the
extract_crc program installed in the
Objective Caml standard library directory.
val clear_available_units : unit -> unit
Clear the list of compilation units accessible to dynamically-linked
val allow_unsafe_modules : bool -> unit
Govern whether unsafe object files are allowed to be
dynamically linked. A compilation unit is ``unsafe'' if it contains
declarations of external functions, which can break type safety.
By default, dynamic linking of unsafe object files is
type linking_error =
Undefined_global of string
| Unavailable_primitive of string
| Uninitialized_global of string
type error =
Not_a_bytecode_file of string
| Inconsistent_import of string
| Unavailable_unit of string
| Linking_error of string * linking_error
| Corrupted_interface of string
exception Error of error
Errors in dynamic linking are reported by raising the
exception with a description of the error.
val error_message: error -> string
Convert an error description to a printable message.