Hi,

long time ago I had problems with stdxxx being in non-blocking i/o mode. The suggestion was to close and re-open the channels from the system units init code.

I ran into this problem again and would like to know:

How can I close and reopen stderr and sdtout from my program?

I want to have some code that is working for sure, regardless of which os and compilerversion is used to translate it.

TIA,
Marc

Don't get me wrong because I formulated somewhat misleading: I'm not asking anyone to write code.

What I need is the knowledge how to access and maybe switch the mode of the system i/o channels.

Marc

close(stderr);
assign(stderr,'');
rewrite(stderr);
close(stdout);
assign(stdout,'');
rewrite(stdout);

This does not enable you to set any particular options on the descriptors though, and I'm not aware of any supported way for doing so (read: a way which is likely to be forward compatible). And even if you could get at the file descriptors, there is also no cross-platform functionality that I'm aware of to change their (non-)blocking setting.

Jonas

As expected it does work but doesn't change blocking behaviour.

and I'm not aware of any supported way for doing so (read: a way which is likely to be forward compatible).

Don't get you here, what do you mean by forward compatible?

And even if you could get at the file descriptors, there is also no cross-platform functionality that I'm aware of to change their (non-)blocking setting.

No, not cross platform, but I was able to make a solution for FreeBSD 4, I assume it'll work (with minor modifications) on other unix-like platforms:

uses unix;
var
  res: longint; // or cint
begin
  res := fpfcntl(TextRec(stderr).Handle, F_GETFL);
  if ((O_NONBLOCK AND res)>0) then
  begin
    res := res AND (NOT O_NONBLOCK);
    res := fpfcntl(TextRec(stderr).Handle, F_SETFL, res);
    if (res=-1) then writeln(stderr, 'ERROR on SETFL');
  end;

This switches the channel to blocking mode and the overrun errors disappear in this case.

Thanks for your help,
Marc