worktable*table= (worktable*)main_arg;

StringInfoDatabuf;

pqsignal(SIGHUP,worker_spi_sighup);

pqsignal(SIGTERM,worker_spi_sigterm);

BackgroundWorkerUnblockSignals();

worker.bgw_start_time=BgWorkerStart_RecoveryFinished;

worker.bgw_restart_time=BGW_NEVER_RESTART;

worker.bgw_main=worker_spi_main;

worker.bgw_sighup=worker_spi_sighup;

worker.bgw_sigterm=worker_spi_sigterm;

The structure <structname>BackgroundWorker</structname> is defined thus:

<programlisting>

typedef void (*bgworker_main_type)(void *main_arg);

typedef void (*bgworker_sighdlr_type)(SIGNAL_ARGS);

typedef struct BackgroundWorker

{

char *bgw_name;

int bgw_restart_time; /* in seconds, or BGW_NEVER_RESTART */

bgworker_main_type bgw_main;

void *bgw_main_arg;

bgworker_sighdlr_type bgw_sighup;

bgworker_sighdlr_type bgw_sigterm;

} BackgroundWorker;

</programlisting>

</para>

passed at registration time.

</para>

<para>

<structfield>bgw_sighup</structfield> and <structfield>bgw_sigterm</> are

pointers to functions that will be installed as signal handlers for the new

process. If <structfield>bgw_sighup</> is NULL, then <literal>SIG_IGN</>

is used; if <structfield>bgw_sigterm</> is NULL, a handler is installed that

will terminate the process after logging a suitable message.

</para>

<para>Once running, the process can connect to a database by calling

<function>BackgroundWorkerInitializeConnection(<parameter>char *dbname</parameter>, <parameter>char *username</parameter>)</function>.

This allows the process to run transactions and queries using the

<para>

Signals are initially blocked when control reaches the

<structfield>bgw_main</> function, and must be unblocked by it; this is to

allow the process tofurthercustomize its signal handlers, if necessary.

allow the process to customize its signal handlers, if necessary.

Signals can be unblocked in the new process by calling

<function>BackgroundWorkerUnblockSignals</> and blocked by calling

<function>BackgroundWorkerBlockSignals</>.

pqsignal(SIGFPE,SIG_IGN);

}

if (worker->bgw_sigterm)

pqsignal(SIGTERM,worker->bgw_sigterm);

pqsignal(SIGTERM,bgworker_die);

if (worker->bgw_sighup)

pqsignal(SIGHUP,worker->bgw_sighup);

pqsignal(SIGHUP,SIG_IGN);

pqsignal(SIGTERM,bgworker_die);

pqsignal(SIGHUP,SIG_IGN);

pqsignal(SIGQUIT,bgworker_quickdie);

InitializeTimeouts();/* establishes SIGALRM handler */

typedefvoid (*bgworker_main_type) (void*main_arg);

typedefvoid (*bgworker_sighdlr_type) (SIGNAL_ARGS);

intbgw_restart_time;/* in seconds, or BGW_NEVER_RESTART */

bgworker_main_typebgw_main;

void*bgw_main_arg;

bgworker_sighdlr_typebgw_sighup;

bgworker_sighdlr_typebgw_sigterm;

}BackgroundWorker;