WSJT-X/lib/timer_C_wrapper.f90
Bill Somerville 95926577ae Make Fortran profiling timer function a callback with a default null implementation
Groundwork for calling the decoders directly from C/C++ threads.

To  access   the  timer   module  timer_module   must  now   be  used.
Instrumented code need  only use the module function  'timer' which is
now a  procedure pointer that  is guaranteed to be  associated (unless
null()  is assigned  to it,  which should  not be  done). The  default
behaviour of 'timer' is to do nothing.

If a  Fortran program  wishes to  profile code it  should now  use the
timer_impl module  which contains a default  timer implementation. The
main program should call 'init_timer([filename])' before using 'timer'
or     calling     routines     that     are     instrumented.      If
'init_timer([filename])'.  If it is called  then an optional file name
may  be  provided  with  'timer.out'  being used  as  a  default.  The
procedure 'fini_timer()' may be called to close the file.

The default  timer implementation is  thread safe if used  with OpenMP
multi-threaded code  so long as  the OpenMP  thread team is  given the
copyin(/timer_private/) attribute  for correct operation.   The common
block /timer_private/ should  be included for OpenMP  use by including
the file 'timer_common.inc'.

The module 'lib/timer_C_wrapper.f90' provides  a Fortran wrapper along
with 'init' and 'fini' subroutines  which allow a C/C++ application to
call timer instrumented  Fortran code and for it  to receive callbacks
of 'timer()' subroutine invocations.  No C/C++ timer implementation is
provided at this stage.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6320 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2015-12-27 15:40:57 +00:00

58 lines
1.7 KiB
Fortran

module timer_c_wrapper
use :: iso_c_binding, only: c_ptr
use timer_module, only: timer, null_timer
implicit none
!
! C interoperable callback setup
!
abstract interface
subroutine c_timer_callback (context, dname, k)
use, intrinsic :: iso_c_binding, only: c_ptr, c_char
implicit none
type(c_ptr), value, intent(in) :: context
character(c_char), intent(in) :: dname(*)
integer, intent(in), value :: k
end subroutine c_timer_callback
end interface
public :: init, fini
private
!
! the following are singleton items which assumes that any timer
! implementation should only assume one global instance, probably a
! struct or class object whose address is stored the context below
!
type(c_ptr), private :: the_context
procedure(C_timer_callback), pointer, private :: the_callback
contains
subroutine timer_callback_wrapper (dname, k)
use, intrinsic :: iso_c_binding, only: c_null_char
implicit none
character(len=8), intent(in) :: dname
integer, intent(in) :: k
call the_callback (the_context, trim (dname) // c_null_char, k)
end subroutine timer_callback_wrapper
subroutine init (context, callback)
use, intrinsic :: iso_c_binding, only: c_ptr, c_funptr, c_f_procpointer
use iso_c_utilities, only: c_to_f_string
use timer_module, only: timer
implicit none
type(c_ptr), value, intent(in) :: context
type(c_funptr), value, intent(in) :: callback
the_context=context
call c_f_procpointer (callback, the_callback)
timer => timer_callback_wrapper
end subroutine init
subroutine fini ()
implicit none
timer => null_timer
end subroutine fini
end module timer_c_wrapper