From c677e18ecf1fecfa60dc126dd43a54cbaf1253cc Mon Sep 17 00:00:00 2001
From: Grzegorz Kowal <grzegorz@amuncode.org>
Date: Thu, 12 Nov 2020 07:22:49 -0300
Subject: [PATCH] INTEGRALS: Add subroutine to flush and sync specific IO unit.

Signed-off-by: Grzegorz Kowal <grzegorz@amuncode.org>
---
 sources/integrals.F90 | 48 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

diff --git a/sources/integrals.F90 b/sources/integrals.F90
index d6d5b19..b86777a 100644
--- a/sources/integrals.F90
+++ b/sources/integrals.F90
@@ -651,7 +651,9 @@ module integrals
                                             , avarr(7), mnarr(7), mxarr(7)
       write(eunit,efmt) step, time, dtn, dte, maxval(errors(:)), errors(:)
 
-      call flush()
+      call flush_and_sync(funit)
+      call flush_and_sync(sunit)
+      call flush_and_sync(eunit)
     end if
 
 #ifdef PROFILE
@@ -663,6 +665,50 @@ module integrals
 !-------------------------------------------------------------------------------
 !
   end subroutine store_integrals
+!
+!===============================================================================
+!
+! subroutine FLUSH_AND_SYNC:
+! -----------------------
+!
+!   Function flushes and fsyncs the I/O buffers.
+!
+!   Arguments:
+!
+!     iounit - the I/O unit to flash;
+!
+!===============================================================================
+!
+  subroutine flush_and_sync(iounit)
+
+    use iso_fortran_env, only : error_unit
+
+    implicit none
+
+    interface
+      function fsync (fd) bind(c,name="fsync")
+      use iso_c_binding, only: c_int
+        integer(c_int), value :: fd
+        integer(c_int) :: fsync
+      end function fsync
+    end interface
+
+    integer, intent(in) :: iounit
+
+    integer :: ret
+
+!-------------------------------------------------------------------------------
+!
+    call flush(iounit)
+
+    ret = fsync(fnum(iounit))
+
+    if (ret /= 0) &
+      write(error_unit,"('Error calling FSYNC for unit:',1i4)") iounit
+
+!-------------------------------------------------------------------------------
+!
+  end subroutine flush_and_sync
 
 !===============================================================================
 !