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.TH "SAM_HC_CALLBACK_REGISTER" 3 "12/01/2009" "corosync Man Page" "Corosync Cluster Engine Programmer's Manual"

.SH NAME
.P
sam_hc_callback_register \- Register health check callback

.SH SYNOPSIS
.P
\fB#include <corosync/sam.h>\fR

.P
\fBcs_error_t sam_hc_callback_register (sam_hc_callback_t cb);\fR

.SH DESCRIPTION
.P
The \fBsam_hc_callback_register\fR function is used to register a user provided
healthcheck callback.  After calling of this function, the SAM is switched
from application driven healthchecking to event driven healthchecking.  In this
mode, \fBsam_hc_send(3)\fR does not need to be executed.

.P
The parameter \fIcb\fR is callback function of type \fIsam_hc_callback_t\fR
defined as:

.nf
  typedef int (*sam_hc_callback_t)(void);
.fi

.P
This function will be regularly called and must return 0 if the process is
functioning normally, or -1 if the process is executing abnormally.  When -1 is
returned, the SAM server execute the registered recovery policy.

.P
A value of NULL can be passed into this function to switch into application
driven healthchecking.
\fIcb\fR to NULL.

.SH RETURN VALUE
.P
This call return CS_OK value if successful, otherwise and error is returned.

.SH ERRORS
.TP
CS_ERR_BAD_HANDLE
SAM was not initialized and registered or health checking is in running state
.TP
CS_ERR_LIBRARY
internal library call failed. This can occur during fork() or pipe() system
calls and the errno variable can be read to retrieve more information.

.SH "SEE ALSO"
.BR sam_start (3),
.BR sam_stop (3),
.BR sam_hc_send (3),
.BR sam_register (3),
.PP

.B CS_ERR_TRY_AGAIN
Resource temporarily unavailable

.B CS_ERR_INVALID_PARAM
Invalid argument

.B CS_ERR_ACCESS
Permission denied

.B CS_ERR_LIBRARY
The connection failed

.B CS_ERR_INTERRUPT
System call interrupted by a signal

.B CS_ERR_NOT_SUPPORTED
The requested protocol/functionality not supported

.B CS_ERR_MESSAGE_ERROR
Incorrect auth message received

.B CS_ERR_NO_MEMORY
Not enough memory to complete the requested task