Remove support for on_exit()

All supported platforms support the C89 standard function atexit()
(SunOS 4 probably being the last one not to), and supporting both
makes the code clumsy.

src/backend/storage/ipc/ipc.c

@@ -39,7 +39,7 @@
 bool		proc_exit_inprogress = false;
 
 /*
- * This flag tracks whether we've called atexit(2) in the current process
+ * This flag tracks whether we've called atexit() in the current process
  * (or in the parent postmaster).
  */
 static bool atexit_callback_setup = false;
@@ -51,7 +51,7 @@ static void proc_exit_prepare(int code);
 /* ----------------------------------------------------------------
  *						exit() handling stuff
  *
- * These functions are in generally the same spirit as atexit(2),
+ * These functions are in generally the same spirit as atexit(),
  * but provide some additional features we need --- in particular,
  * we want to register callbacks to invoke when we are disconnecting
  * from a broken shared-memory context but not exiting the postmaster.
@@ -234,8 +234,6 @@ shmem_exit(int code)
  * postmaster treat it as a crash --- see pmsignal.c.
  * ----------------------------------------------------------------
  */
-#ifdef HAVE_ATEXIT
-
 static void
 atexit_callback(void)
 {
@@ -243,15 +241,6 @@ atexit_callback(void)
 	/* ... too bad we don't know the real exit code ... */
 	proc_exit_prepare(-1);
 }
-#else							/* assume we have on_exit instead */
-
-static void
-atexit_callback(int exitstatus, void *arg)
-{
-	/* Clean up everything that must be cleaned up */
-	proc_exit_prepare(exitstatus);
-}
-#endif   /* HAVE_ATEXIT */
 
 /* ----------------------------------------------------------------
  *		on_proc_exit
@@ -275,11 +264,7 @@ on_proc_exit(pg_on_exit_callback function, Datum arg)
 
 	if (!atexit_callback_setup)
 	{
-#ifdef HAVE_ATEXIT
 		atexit(atexit_callback);
-#else
-		on_exit(atexit_callback, NULL);
-#endif
 		atexit_callback_setup = true;
 	}
 }
@@ -306,11 +291,7 @@ on_shmem_exit(pg_on_exit_callback function, Datum arg)
 
 	if (!atexit_callback_setup)
 	{
-#ifdef HAVE_ATEXIT
 		atexit(atexit_callback);
-#else
-		on_exit(atexit_callback, NULL);
-#endif
 		atexit_callback_setup = true;
 	}
 }

src/bin/psql/input.c

@@ -45,12 +45,7 @@ static int	history_lines_added;
 #define NL_IN_HISTORY	0x01
 #endif
 
-#ifdef HAVE_ATEXIT
 static void finishInput(void);
-#else
-/* designed for use with on_exit() */
-static void finishInput(int, void *);
-#endif
 
 
 /*
@@ -313,11 +308,7 @@ initializeInput(int flags)
 	}
 #endif
 
-#ifdef HAVE_ATEXIT
 	atexit(finishInput);
-#else
-	on_exit(finishInput, NULL);
-#endif
 }
 
 
@@ -416,11 +407,7 @@ saveHistory(char *fname, int max_lines, bool appendFlag, bool encodeFlag)
 
 
 static void
-#ifdef HAVE_ATEXIT
 finishInput(void)
-#else
-finishInput(int exitstatus, void *arg)
-#endif
 {
 #ifdef USE_READLINE
 	if (useHistory && psql_history)

src/include/pg_config.h.in

@@ -90,9 +90,6 @@
 /* Define to 1 if you have the `append_history' function. */
 #undef HAVE_APPEND_HISTORY
 
-/* Define to 1 if you have the `atexit' function. */
-#undef HAVE_ATEXIT
-
 /* Define to 1 if you have the `cbrt' function. */
 #undef HAVE_CBRT
 
@@ -369,9 +366,6 @@
 /* Define to 1 if you have the <net/if.h> header file. */
 #undef HAVE_NET_IF_H
 
-/* Define to 1 if you have the `on_exit' function. */
-#undef HAVE_ON_EXIT
-
 /* Define to 1 if you have the <ossp/uuid.h> header file. */
 #undef HAVE_OSSP_UUID_H
 

src/include/pg_config.h.win32

@@ -72,9 +72,6 @@
 # define gettimeofday(a,b) gettimeofday(a)
 #endif
 
-/* Define to 1 if you have the `atexit' function. */
-#define HAVE_ATEXIT 1
-
 /* Define to 1 if you have the `cbrt' function. */
 //#define HAVE_CBRT 1
 
@@ -279,9 +276,6 @@
 /* Define to 1 if you have the <netinet/tcp.h> header file. */
 /* #undef HAVE_NETINET_TCP_H */
 
-/* Define to 1 if you have the `on_exit' function. */
-/* #undef HAVE_ON_EXIT */
-
 /* Define to 1 if you have the <pam/pam_appl.h> header file. */
 /* #undef HAVE_PAM_PAM_APPL_H */