Add exit_case support-test

This test can be used to test several important "flavors" of PRIF
exit, along with exit codes and buffered output.

Author: bonachea

example/support-test/exit_case.F90

@@ -0,0 +1,48 @@
+program hello_world
+  use iso_c_binding, only: c_bool
+  use iso_fortran_env, only: output_unit,error_unit
+  use prif, only : &
+     prif_init &
+    ,prif_this_image_no_coarray &
+    ,prif_num_images &
+    ,prif_stop &
+    ,prif_error_stop &
+    ,prif_sync_all
+  implicit none
+
+  integer :: init_exit_code, me, num_imgs, exitcase = 1
+  logical(kind=c_bool), parameter :: false = .false._c_bool, true = .true._c_bool
+  character(len=256) :: arg_string
+
+  call prif_init(init_exit_code)
+  if (init_exit_code /= 0) call prif_error_stop(quiet=false, stop_code_char="program startup failed")
+
+  call prif_this_image_no_coarray(this_image=me)
+  call prif_num_images(num_images=num_imgs)
+  if (command_argument_count() > 0) then
+    call get_command_argument(1, arg_string)
+    read(arg_string, *) exitcase
+  end if
+  if (me == 1) write(output_unit,*) "testing exit case ", exitcase
+  
+  call prif_sync_all()
+
+  write(output_unit,'(A,I1,A,I1)') "stdout from image ", me, " of ", num_imgs
+  write(error_unit,'(A,I1,A,I1)')  "stderr from image ", me, " of ", num_imgs
+
+  call prif_sync_all()
+
+  select case (exitcase) 
+  case (1)
+    call prif_stop(quiet=true, stop_code_int=exitcase+100)
+  case (2)
+    call prif_stop(quiet=false, stop_code_int=exitcase+100)
+  case (3)
+    if (me == num_imgs) call prif_error_stop(quiet=true, stop_code_int=exitcase+100)
+  case default
+    if (me == num_imgs) call prif_error_stop(quiet=false, stop_code_int=exitcase+100)
+  end select
+
+  call prif_sync_all()
+
+end program