[Rd] R Console Bug?

[Simon Urbanek]

Sorry, unable to reproduce on macOS, in R console:

> dyn.load("test.so")
> .Call("printtest",1e4L)

   Processing data chunk 1 of 3
 [==============================] 100%

   Processing data chunk 2 of 3
 [==============================] 100%

   Processing data chunk 3 of 3
 [==============================] 100%
NULL

But honestly I'm not sure sure I understand the report. R_FlushConsole is a no-op for terminal console and your code just prints on stderr anyway (which is not buffered). All this does is just a lot of \r output (which is highly inefficient anywhere but in Terminal by definition). Can you clarify what the code tries to trigger?

Cheers,
Simon


> On Apr 16, 2021, at 23:11, Morgan Morgan <morgan.emailbox using gmail.com> wrote:
> 
> Hi,
> 
> I am getting a really weird behaviour with the R console.
> Here is the code to reproduce it.
> 
> 1/ C code: ---------------------------------------------------
> 
> SEXP printtest(SEXP x) {
>  const int PBWIDTH = 30, loop = INTEGER(x)[0];
>  int val, lpad;
>  double perc;
>  char PBSTR[PBWIDTH], PBOUT[PBWIDTH];
>  memset(PBSTR,'=', sizeof(PBSTR));
>  memset(PBOUT,'-', sizeof(PBOUT));
>  for (int k = 0; k < 3; ++k) {
>    REprintf("\n   Processing data chunk %d of 3\n",k+1);
>    for (int i = 0; i < loop; ++i) {
>      perc = (double) i/(loop-1);
>      val  = (int) (perc * 100);
>      lpad = (int) (perc * PBWIDTH);
>      REprintf("\r [%.*s%.*s] %3d%%", lpad, PBSTR, PBWIDTH - lpad, PBOUT,
> val);
>      R_FlushConsole();
>    }
>    REprintf("\n");
>  }
>  return R_NilValue;
> }
> 
> 2/ Build so/dll: ---------------------------------------------------
> 
> R CMD SHLIB
> 
> 3/ Run code :  ---------------------------------------------------
> 
> dyn.load("test.so")
> .Call("printtest",1e4L)
> dyn.unload("test.so")
> 
> 4/ Issue:  ---------------------------------------------------
> If you run the above code in RStudio, it works well both on Mac and Windows.
> If you run it in Windows cmd, it is slow.
> If you run it in Windows RGui, it is slow but also all texts are flushed.
> If you run it in Mac terminal, it runs perfectly.
> If you run it in Mac R Console, it prints something like :
>> .Call("printtest",1e4L)
> [==============================] 100%NULL----------------------------]   0%
> 
> I am using R 4.0.4 (Mac) / 4.0.5 (Windows)
> 
> Is that a bug or am I doing something wrong?
> 
> Thank you
> Best regards,
> Morgan
> 
> 	[[alternative HTML version deleted]]
> 
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