0004104: Condition.timedwait missing in threads library

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0004104

OCaml

OCaml general

public

2006-09-08 21:52

2006-09-11 11:18

Reporter

mottl

Assigned To

Priority

normal

Severity

feature

Reproducibility

always

Status

acknowledged

Resolution

open

Platform

OS Version

Product Version

3.09.3

Target Version

Fixed in Version

Summary

0004104: Condition.timedwait missing in threads library

Description

The POSIX-standard supports the function pthread_cond_timedwait, which would be very useful for many systems applications. The POSIX-threads version is trivial to write (took me only a few minutes) so it would be great if it could be made part of the standard distribution.

I don't know how hard it would be to implement for byte code threads, but most people probably don't care much about the latter anyway so one could just leave it unimplemented for those if it's too time consuming to do right now.

Additional Information

The function interface (the function returns false on timeouts):

  val timedwait : Condition.t -> Mutex.t -> float -> bool

Here is the C-stub:

  CAMLprim value caml_condition_timedwait(value v_cnd, value v_mtx, value v_timeo)
  {
    CAMLparam2(v_cnd, v_mtx);
      int ret;
      pthread_cond_t *cnd = Condition_val(v_cnd);
      pthread_mutex_t *mtx = Mutex_val(v_mtx);
      double timeo = Double_val(v_timeo);
      struct timespec ts;
      ts.tv_sec = timeo;
      ts.tv_nsec = (timeo - ts.tv_sec) * 1e9;
      enter_blocking_section();
        ret = pthread_cond_timedwait(cnd, mtx, &ts);
      leave_blocking_section();
      if (ret == ETIMEDOUT) CAMLreturn(Val_false);
      caml_pthread_check(ret, "Condition.timedwait");
    CAMLreturn(Val_true);
  }

Note that the timeout parameter is an absolute time for good reason (see the man page for this function to know why) so the OCaml-interface should keep this specification.

Issue History
Date Modified	Username	Field	Change
2006-09-08 21:52	mottl	New Issue
2006-09-11 11:18	doligez	Status	new => acknowledged

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