19.2.267. PMIx_server_delete_process_set

PMIx_server_delete_process_set — Delete a PMIx process set name.

19.2.267.1. SYNOPSIS

#include <pmix_server.h>

pmix_status_t PMIx_server_delete_process_set(char *pset_name);

19.2.267.1.1. Python Syntax

from pmix import *

foo = PMIxServer()
# ... after a successful foo.init() ...
rc = foo.delete_process_set('myset')

19.2.267.2. INPUT PARAMETERS

pset_name: NULL-terminated string name of the process set being deleted.

19.2.267.3. DESCRIPTION

Provide a function by which the host environment can delete a process set name previously created with PMIx_server_define_process_set(3). Deleting the name has no impact on the member processes themselves — it simply removes the label and its associated membership record from the local PMIx server.

When called, the PMIx server library removes the corresponding entry from its internal list of process sets, then alerts all local clients to the deletion by generating a PMIX_PROCESS_SET_DELETE event carrying the PMIX_PSET_NAME attribute (the name of the deleted set). The removal comes first so that a handler cannot observe a set that has been announced as gone but is still being reported by PMIX_QUERY_PSET_NAMES. If no set with the given name is currently recorded, the notification is still issued and the call completes successfully.

PMIx_server_delete_process_set is a blocking call. Internally it thread-shifts the request onto the PMIx progress thread, removes the recorded set, emits the local notification, and returns once that processing is complete.

19.2.267.4. RETURN VALUE

Returns one of the following:

PMIX_SUCCESS — the deletion was processed. As with PMIx_server_define_process_set(3), the local notification is a courtesy and a failure to build or deliver it does not fail the deletion.
PMIX_ERR_BAD_PARAM — pset_name was NULL.
PMIX_ERR_INIT — the PMIx server library has not been initialized.
PMIX_ERR_NOT_AVAILABLE — the library’s progress engine has been stopped, so the request cannot be serviced.

PMIx error constants are defined in pmix_common.h.

19.2.267.5. NOTES

This API is restricted to the server role and must be called only after a successful PMIx_server_init(3).

The host environment is responsible for ensuring consistent knowledge of process set membership across all involved PMIx servers. The PMIx library only removes the definition on the local server; it does not propagate the deletion to peer servers.

19.2.267.6. PROGRESS THREAD RESTRICTION

A blocking PMIx call must not be made from within the PMIx progress thread. Any code the library itself invokes runs on that thread: an event handler registered through PMIx_Register_event_handler(3), a callback passed to a non-blocking PMIx API, and — in a server or tool — the completion of a host-module up-call. A blocking call waits for work that the progress thread has to perform, so making one from that thread waits for itself and never returns. The PMIx Standard disallows it, and there is no way for an implementation to service such a request.

Where this call has a blocking form — including the blocking behavior a non-blocking entry point adopts when it is passed a NULL cbfunc — that form detects the situation and returns PMIX_ERR_WOULD_BLOCK immediately, accompanied by a diagnostic naming the call. Nothing is done and no callback is invoked.

PMIX_ERR_WOULD_BLOCK here is not a transient condition to retry: it reports a call that cannot be serviced from where it was made. Reissue it as the non-blocking form with a callback, or from a thread of your own.