ham_action_handle(), ham_action_handle_node()

Get a handle to an action in a condition in an entity


#include <ha/ham.h>

ham_action_t *ham_action_handle(int nd,
                                const char *ename, 
                                const char *cname, 
                                const char *aname, 
                                unsigned flags);

ham_action_t *ham_action_handle_node(int nd,
                                const char *nodename, 
                                const char *ename, 
                                const char *cname, 
                                const char *aname, 
                                unsigned flags);




The ham_action_handle() function returns a handle to an action (aname) in a condition (cname) in an entity (ename).

You can pass the handle obtained from this function to other functions that expect a handle (e.g. ham_action_remove() or ham_action_handle_free()).

Note: 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_action_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.


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


The name given in ename, cname, or aname is invalid (e.g. it contains the / character), or cname or aname is NULL.
The name given 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.
There's no action of the name aname in a condition cname defined in an entity ename in the HAM's current context.
Not enough memory to create a new handle.


QNX Neutrino

Cancellation point No
Interrupt handler No
Signal handler No
Thread Yes


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

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

See also:

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