char2int Function

    integer function char2int( lstring, strloc, localrc )
    !---------------------------------------------------------------------------
    ! This function converts a character representation of an integer digit
    ! between 0-9 into its integer equivalent. Optional argument of character
    ! address allows selection of individual characters in a string. Default
    ! assumes conversion of the first character of the string.
    !---------------------------------------------------------------------------

    ! arguments
    character(len=*), intent(in   )           :: lstring
    integer,          intent(in   ), optional :: strloc
    integer,          intent(inout)           :: localrc

    ! local variables
    integer :: ntemp, sloc

    ! initialize variables
    localrc = ESMF_RC_NOT_IMPL

    if(present(strloc) ) then
       sloc = strloc
    else
       sloc = 1
    endif   
    
 !------------------------------------------------------------------------------
    !---------------------------------------------------------------------------
    ! Convert string to integer
    !---------------------------------------------------------------------------
    ntemp = iachar( lstring(sloc:sloc) )-iachar('0')
    
    ! check to see that values is within the acceptable range
    if ( ntemp < 0 .and. ntemp > 9 ) then
       call ESMF_LogSetError( ESMF_FAILURE,                                 &
                 msg="character is not a digit between 0 and 9",                   &
                 rcToReturn=localrc)
        return
       char2int = 0
    else
       char2int = ntemp
    endif
    
    !---------------------------------------------------------------------------
    ! if I've gotten this far without an error, then the routine has succeeded.
    !---------------------------------------------------------------------------
    localrc = ESMF_SUCCESS

    return
    
    !---------------------------------------------------------------------------
    end function char2int