sam_register (3) - Linux Manuals

sam_register: Register component for health checking


sam_rehister - Register component for health checking


#include <corosync/sam.h>

cs_error_t sam_register (unsigned int *instance_id);


The sam_register function is used to register a process for healthchecking. If recovery policy is set to SAM_RECOVERY_POLICY_RESTART and recovery action will be taken, the new process instance will begin execution at the next code line after this function is called.

This function can be called only once and SAM must be initialized by sam_initialize(3) function.

The instance_id argument is a pointer to a value storing the current iteration instance. If this parameter is NULL, no instance_id is returned. and then, no instance_id will be returned. This value starts at 0 for the first iteration instance, and increases by 1 each time a recovery restart is executed. After reaching MAX_INT, the instance_id will reset to 0.

The placement of this function is important because after it is called, the process id will change.

After registration, event driven health checking is not running.


This call return CS_OK value if successful, otherwise and error is returned.


health checking was not started by calling sam_start(3) function.
internal library call failed. This can be one of pipe creation or fork. It's possible to get more information from errno.


sam_start(3), sam_initialize(3), sam_hc_callback_register(3)

CS_ERR_TRY_AGAIN Resource temporarily unavailable

CS_ERR_INVALID_PARAM Invalid argument

CS_ERR_ACCESS Permission denied

CS_ERR_LIBRARY The connection failed

CS_ERR_INTERRUPT System call inturrupted by a signal

CS_ERR_NOT_SUPPORTED The requested protocol/functuality not supported

CS_ERR_MESSAGE_ERROR Incorrect auth message received

CS_ERR_NO_MEMORY Not enough memory to completed the requested task