＜CRITICAL Example Program＞

Module module
  Logical :: finished = .False.
  Integer :: count[*] = 0
Contains
  Subroutine do_some_work
    ! Just increment the count on image one, safely.
    Critical
      ! We only read or write the value of count[1] inside this
      ! Critical block, so only one image at a time.
      If (count[1]==100) Then
        finished = .True.
      Else
        count[1] = count[1] + 1
      End If
    End Critical
  End Subroutine
End Module
Program critical_example
  Use module
  ! All images will do this.
  Do While (.Not.finished)
    Call do_some_work
  End Do
  If (This_Image()==1) Then
    Print 1,count
1   Format(1X,'Finished ',I0,' units of work')
  End If
End Program

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■ Execution Results

 Finished 100 units of work