module Netmcore_process:sig..end
Statically typed processes
This module provides a slightly higher-level view on processes,
but is also a bit more restricted than the primitives in
Netmcore.
Please read Netmcore_basics for an introduction into using
this module. There is also Netmcore_tut with more advanced
techniques.
type 'a fork_point
A fork point can start a new process with argument 'a
type 'b join_point
A join point can wait until a process finishes with a result 'b
val def_process : ('a -> 'b) -> 'a fork_point * 'b join_pointlet (fp,jp) = def_process proc: Defines a process (which must happen
in the master process), so that:
let pid = start fp arg: Starts the new process and passes the
argument arg to it. The process runs proc arg which will
finally result in a value rlet r_opt = join jp pid: Waits until the process identified by
pid finishes, and returns the result as r_opt = Some r.
On error, it returns None.def_process should be called at module initialization time
before any process is started. This interface is not designed for
calling def_process later.
val start : ?inherit_resources:Netmcore.inherit_request ->
'a fork_point -> 'a -> Netmcore.process_idlet pid = start fp arg: Starts a new process at the fork point
fp with argument arg. This means that the process is forked
from the master process, and that the value of arg is sent to it
using Marshal. The returned process ID is Netmulticore's own
ID and not to be confused with the ID assigned by the operating
system.
Option inherit_resources: Certain resources are only accessible by
the process when they are inherited to it. This is the case for
`Posix_shm_preallocated. This can be set to `All to inherit
all inheritable resources, or to `Resources l to only inherit
the resources of l. By default, no resources are inherited.
val join : 'b join_point -> Netmcore.process_id -> 'b optionlet r_opt = join jp pid: Waits until the process pid finishes,
and uses the join point jp to extract the result. The result
is returned as Some r on success, and None on error.
Result values are transmitted from the joining process to
this function using Marshal. Errors include uncaught exceptions
as well as unexpected process termination (exit, signal).
If the process referenced by pid is not an instance that belongs
to jp, the function will fail.
This function must not be called from the master process (which is not allowed to block until a result is available).
val join_nowait : 'b join_point -> Netmcore.process_id -> 'b optionLike join, but it is not waited for the termination of the process.
If the process is not yet done, this function returns None.
It also returns None if the process terminated with an error or did
not set a result value for other reasons.
Unlike join, this function can be called in the master process.
val release_fork_point : 'a fork_point -> unitReleases a fork point so it is deleted from the internal resource table.
val release_join_point : 'b join_point -> unitReleases a join point so it is deleted from the internal resource table.
