[R-pkg-devel] is Fortran write still strictly forbidden?

[Berend Hasselman]

Hi,

Have a look at package nleqslv to see how you can avoid Fortran write completely.
Look at the file src/nwout.c and the calls of various functions therein in the other fortran files.

regards,

Berend Hasselman

> On 08-05-2024, at 10:37, Jisca Huisman <jisca.huisman using gmail.com> wrote:
> 
> Hello,
> 
> I like to use write() in Fortran code to combine text with some integers 
> & doubles, to pass runtime information to R in a way that is prettier 
> and more legible than with intpr() & dblepr(). In the past any calls to 
> write() were strictly forbidden in Fortran code, as apparently it messed 
> something up internally (I cannot recall the details). But from 'writing 
> R extensions' it seems that there have been quite a few changes with 
> respect to support for Fortran code, and it currently reads:
> 
> 
> 6.5.1 Printing from Fortran
> 
> On many systems Fortran|write|and|print|statements can be used, but the 
> output may not interleave well with that of C, and may be invisible 
> onGUIinterfaces. They are not portable and best avoided.
> 
> 
> To be more specific, would the subroutine below be allowed? Is it needed 
> to declare R >= 4.0 (?) in the package DESCRIPTION (& then use labelpr() 
> instead of intpr() ?) Is there an alternative without write() to get the 
> same result?
> 
> 
> subroutine Rprint_pretty(iter, x)
>     integer, intent(IN) :: iter
>     double precision, intent(IN) :: x
>     integer :: date_time_values(8), nchar, IntDummy(0)
>     character(len=8) :: time_now
>     character(len=200) :: msg_to_R
> 
>     call date_and_time(VALUES=date_time_values)
>     write(time_now, '(i2.2,":",i2.2,":",i2.2)') date_time_values(5:7)
>     write(msg_to_R, '(a8, " i: ", i5, "  value: ", f8.2)') time_now, 
> iter, x
> 
>     nchar = len(trim(msg_to_R))
>    call intpr(trim(msg_to_R), nchar, IntDummy, 0)
> 
>   end subroutine Rprint_pretty
> 
> 
> Thanks!
> 
> 
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> 
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