ham_condition_handle(), ham_condition_handle_node()

Get a handle to a condition in an entity

Synopsis:

#include <ha/ham.h>

ham_condition_t *ham_condition_handle( 
                    int nd,
                    const char *ename, 
                    const char *cname, 
                    unsigned flags );

ham_condition_t *ham_condition_handle_node( 
                    const char *nodename, 
                    const char *ename, 
                    const char *cname, 
                    unsigned flags );

Library:

libham

Description:

The ham_condition_handle() function returns a handle to a condition (cname) in an entity (ename).

The handle obtained from this function can be passed to other functions, such as ham_action_restart() or ham_condition_handle_free().

---

To get a handle for a global entity, pass NULL for ename.

---

The handle returned is opaque — its contents are internal to the library.

If a node (nd) is specified, the handle is to an entity/condition/action combination that refers to a process on that remote node. The ham_condition_handle_node() function is used when a nodename is used to specify a remote HAM instead of a node identifier (nd).

There are no flags defined at this time.

Returns:

A valid ham_condition_t, or NULL if an error occurred (errno is set).

Errors:

EINVAL

The name given in cname or ename is invalid (e.g. it contains the “/” character), or cname 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.

ENOENT

There's no condition by the name cname defined in an entity by name ename in the current context of the HAM.

ENOMEM

Not enough memory to create a new handle.

Classification:

QNX Neutrino

Caveats:

A call to ham_condition_handle() and a subsequent use of the handle returned in a call such as ham_action_restart() are completely asynchronous. Therefore, a valid action/condition/entity may no longer exist when the handle is used to attach actions at a later time.

In such an event, the ham_action*() functions will return an error (ENOENT) that the condition doesn't exist in the given entity.

See also:

ham_action_execute(), ham_action_handle(), ham_action_handle_free(), ham_action_notify_pulse(), ham_action_notify_signal(), ham_action_remove(), ham_action_restart(), ham_action_waitfor(), ham_condition_handle_free(), ham_entity_handle(), ham_entity_handle_free()