On Fri, 9 Dec 2011, tcoq wrote:
Hello,
I'm trying to poll the input stream to see whether there is a new character
available, without blocking my software.
I've tried "Read" and "THandleStream.ReadByte" but with no success: when the
input is empty, the program just waits.
Is there a way to ask whether the input stream is not empty, without waiting
and without using threads/processes?
And, in addition, is there an OS-independent way (linux, windows)?
something like:
var
inputStream: THandleStream;
aByte: Byte;
begin
InputStream := THandleStream.Create(StdInputHandle);
try
while true do
begin
{$I-}
aByte := InputStream.ReadByte;
DoSomethingWithByte(aByte);
result := true;
end;
except
On E: EStreamError do result := false;
end;
//This code here is never executed
ThereIsNothingInInputStream_DoDefault;
end;
You must use fpSelect() or Poll on the handle on linux/unix.
On windows, you'll need to WaitForObject() or so on the file handle.
Michael.
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