package algaeff

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The signature of mutex effects.

exception Locked

The exception raised by exclusively if the mutex was locked.

val exclusively : (unit -> 'a) -> 'a

exclusively f locks the mutex, run the thunk f, and then unlock the mutex. If the mutex was already locked, exclusively f immediately raises Locked without waiting. Note that calling exclusively inside f is an instance of attempting to lock an already locked mutex.

  • raises Locked

    The mutex was already locked.

val run : (unit -> 'a) -> 'a

run f executes the thunk f which may perform mutex effects. Each call of run creates a fresh mutex; in particular, calling run inside the thunk f will start a new scope that does not interfere with the outer scope.

val register_printer : ([ `Exclusively ] -> string option) -> unit

register_printer p registers a printer p via Printexc.register_printer to convert unhandled internal effects into strings for the OCaml runtime system to display. Ideally, all internal effects should have been handled by run and there is no need to use this function, but when it is not the case, this function can be helpful for debugging. The functor Mutex.Make always registers a simple printer to suggest using run, but you can register new ones to override it. The return type of the printer p should return Some s where s is the resulting string, or None if it chooses not to convert a particular effect. The registered printers are tried in reverse order until one of them returns Some s for some s; that is, the last registered printer is tried first. Note that this function is a wrapper of Printexc.register_printer and all the registered printers (via this function or Printexc.register_printer) are put into the same list.

The input type of the printer p is a variant representing internal effects used in this module. It corresponds to all the effects trigger by exclusively.

  • since 1.1.0