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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 regulargly 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),