[patch, committed] PR55795 Re: Buffered/unbuffered I/O issues

[Jerry DeLisle]

I reviewed, tested, regression tested, and OKed this patch for FX.

I also updated gfortran.texi to reflect the fix.

See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33795 for further info.

Regards,

Jerry

François-Xavier Coudert wrote:
>> Something like GFORTRAN_UNBUFFERED_STDIO would be perfect.
> 
> If think it's OK as it's rather contained. I'd call it
> GFORTRAN_UNBUFFERED_PRECONNECTED, though, because that's what it
> really is in Fortran terms. Possible implementation follows (caveat,
> not even built because I wrote it in the train)...
> 
> 
> Index: libgfortran.h
> ===================================================================
> --- libgfortran.h       (revision 129403)
> +++ libgfortran.h       (working copy)
> @@ -349,7 +349,7 @@ typedef struct
>    int separator_len;
>    const char *separator;
> 
> -  int use_stderr, all_unbuffered, default_recl;
> +  int use_stderr, all_unbuffered, unbuffered_preconnected, default_recl;
>    int fpe, dump_core, backtrace;
>  }
>  options_t;
> Index: io/unix.c
> ===================================================================
> --- io/unix.c   (revision 129403)
> +++ io/unix.c   (working copy)
> @@ -1411,10 +1411,16 @@ input_stream (void)
>  stream *
>  output_stream (void)
>  {
> +  stream * s;
> +
>  #if defined(HAVE_CRLF) && defined(HAVE_SETMODE)
>    setmode (STDOUT_FILENO, O_BINARY);
>  #endif
> -  return fd_to_stream (STDOUT_FILENO, PROT_WRITE);
> +
> +  s = fd_to_stream (STDOUT_FILENO, PROT_WRITE);
> +  if (options.unbuffered_preconnected)
> +    ((unix_stream *) s)->unbuffered = 1;
> +  return s;
>  }
> 
> 
> @@ -1424,10 +1430,16 @@ output_stream (void)
>  stream *
>  error_stream (void)
>  {
> +  stream * s;
> +
>  #if defined(HAVE_CRLF) && defined(HAVE_SETMODE)
>    setmode (STDERR_FILENO, O_BINARY);
>  #endif
> -  return fd_to_stream (STDERR_FILENO, PROT_WRITE);
> +
> +  s = fd_to_stream (STDERR_FILENO, PROT_WRITE);
> +  if (options.unbuffered_preconnected)
> +    ((unix_stream *) s)->unbuffered = 1;
> +  return s;
>  }
> 
> 
> Index: runtime/environ.c
> ===================================================================
> --- runtime/environ.c   (revision 129403)
> +++ runtime/environ.c   (working copy)
> @@ -379,6 +379,10 @@ static variable variable_table[] = {
>     "If TRUE, all output is unbuffered.  This will slow down large writes "
>     "but can be\nuseful for forcing data to be displayed immediately.", 0},
> 
> +  {"GFORTRAN_UNBUFFERED_PRECONNECTED", 0, &options.unbuffered_preconnected,
> +   init_boolean, show_boolean,
> +   "If TRUE, output to preconnected units is unbuffered.", 0},
> +
>    {"GFORTRAN_SHOW_LOCUS", 1, &options.locus, init_boolean, show_boolean,
>     "If TRUE, print filename and line number where runtime errors happen.", 0},
> 
> 
> We also need to remove check_buffered(), of course, and audit for
> other dead code in runtime/environ.c.
>