ham_attach_self()

Updated: May 06, 2022

Attach an application as a self-attached entity

Synopsis:

#include <ha/ham.h>

ham_entity_t *ham_attach_self(
                 const char *ename, 
                 uint64_t hp,
                 int hpdl, 
                 int hpdh, 
                 unsigned flags );

Arguments:

ename
The name of the entity. This must be unique across the whole context of the HAM.
hp
The heartbeat interval in nanoseconds. The lowest permissible heartbeat interval is defined in the constant HAMHBEATMIN (see <ha/ham.h>). Use 0 if no heartbeat is desired.
Note: Note that here you're specifying the heartbeat interval — the client must still call the ham_heartbeat() function to actually transmit the heartbeat.
hpdl
The number of missed heartbeats that will trigger a CONDHBEATMISSEDLOW condition, or 0 to disable the condition. The value of hpdl must be hpdh.
hpdh
As for hpdl, but for CONDHBEATMISSEDHIGH. The value of hpdh must be hpdl.
flags
There are no flags defined at this time.

Library:

libham

Description:

You use the ham_attach_self() call to attach an application as a self-attached entity to the HAM. Self-attached entities can, on their own, decide at exactly what point in their lifespan they want to be monitored, what conditions they want acted upon, and when they want to stop the monitoring. Self-attached entities can also specify an interval at which they'll send heartbeats to the HAM. The heartbeat can be used to detect unresponsive processes that aren't dead.

Once an entity has been attached, you can add conditions and actions to it.

Note: Since the ham_attach*() functions open a connection to the HAM, for convenience they also perform the initial ham_connect() call. So any client that makes a ham_attach_self() call doesn't need to call ham_connect() or ham_disconnect() before and after the call to ham_attach_self().

Returns:

A valid handle to an entity on success; otherwise, NULL (errno is set).

Errors:

EBADF
Couldn't connect to the HAM.
EEXIST
The name provided for the entity already exists.
EINVAL
The name given in ename is invalid (e.g., it contains the / character) or is NULL.
ENAMETOOLONG
The name given (in aname) is too long, i.e. it exceeds _POSIX_PATH_MAX (defined in <limits.h>). Note that the combined length of an entity/condition/action name is also limited by _POSIX_PATH_MAX.
ENOMEM
Not enough memory to create a new handle.

In addition to the above errors, the HAM returns any error it encounters while servicing the request to add a new entity to its context.

Classification:

QNX Neutrino

Safety:  
Cancellation point No
Interrupt handler No
Signal handler No
Thread Yes