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BJ
Guest
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 Posted: Sat Apr 07, 2007 7:08 am Post subject: SendBuf Socket Delay |
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Hello,
The code below I borrow it from Gambit which works great. But I
want to delay the sending every 100 bytes for 100 millisecond.
Is having a Sleep function in the loop a correct way to do it?
I am afraid that the Sleep function in my code will hang the
application and not delay the sending of 100 bytes.
bool __fastcall TEthernet::SendStream(TCustomWinSocket *Socket, TStream *Stream)
{
BYTE buffer[100]; //1024
int Size = Stream->Size;
AnsiString tempBuffer = "";
int NumWrite = 0;
int NumToSend = (Size - Stream->Position);
try
{
while( NumToSend > 0 )
{
int NumRead = Stream->Read(buffer, min(NumToSend, sizeof(buffer)));
if( NumRead < 1 )
return false;
NumWrite = SendBuf(Socket, buffer, NumRead);
if( !NumWrite )
return false;
else
{
tempBuffer = "num sent: " + NumWrite;
StatusFromPrinterMemo->Lines->Add(tempBuffer);
}
NumToSend -= NumRead;
Sleep(100);
}
}
catch(const Exception &)
{
return false;
}
return true;
} |
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chenzero
Guest
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| Posted: Sat Apr 07, 2007 7:08 am Post subject: Re: SendBuf Socket Delay |
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"BJ" <caophong (AT) gmail (DOT) com> 写入消息新闻:4616ef1d$1 (AT) newsgroups (DOT) borland.com...
Hello,
The common solution for executing a long time task in the "main" thread
which
freezes the UI is executing the long time task in another thread.
In c++builder, there is a class named "TThread" for convinent use. however,
in my opinion, it's always not easy to write a bug free multi-threading
program.
On the net, there are lots of resources on discussing how to write
multi-thread
program,a good article is:
http://cc.codegear.com/Item.aspx?id=14809
hope it helps.
zero |
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Remy Lebeau (TeamB)
Guest
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| Posted: Sat Apr 07, 2007 7:24 am Post subject: Re: SendBuf Socket Delay |
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"BJ" <caophong (AT) gmail (DOT) com> wrote in message
news:4616ef1d$1 (AT) newsgroups (DOT) borland.com...
| Quote: | The code below I borrow it from Gambit which works great. But
I want to delay the sending every 100 bytes for 100 millisecond.
Is having a Sleep function in the loop a correct way to do it?
|
Yes.
| Quote: | I am afraid that the Sleep function in my code will hang the
application
|
The code you are using was intentially designed to block the calling
thread until the function exits. So if you are calling it in the
context of the main thread, then the application will appear frozen
until the function exits. Putting a Sleep() into the loop does not
change that, only makes it more noticable to the user. That is why I
don't normally use sockets in the main thread to begin with.
| Quote: | and not delay the sending of 100 bytes.
|
It will definately delay the sending.
| Quote: | NumWrite = SendBuf(Socket, buffer, NumRead);
if( !NumWrite )
return false;
|
You are not checking to see if SendBuf() returns < 0, which indicates
a socket error. Using the '!' operator like that will only be able to
detect a result of 0, which indicated a graceful socket disconnect
occured.
Gambit |
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BJ
Guest
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| Posted: Sat Apr 07, 2007 8:10 am Post subject: Re: SendBuf Socket Delay |
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Hi Guys,
Yeah...working with thread will be more stable. But my
application is pretty small. I don't care if my application
hang at all, just as long as it completely sends out the 100
bytes and wait for 100milisecond. I am happy. |
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Chris Uzdavinis (TeamB)
Guest
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| Posted: Mon Apr 09, 2007 6:36 pm Post subject: Re: SendBuf Socket Delay |
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"Remy Lebeau \(TeamB\)" <no.spam (AT) no (DOT) spam.com> writes:
| Quote: | The code you are using was intentially designed to block the calling
thread until the function exits. So if you are calling it in the
context of the main thread, then the application will appear frozen
until the function exits. Putting a Sleep() into the loop does not
change that, only makes it more noticable to the user. That is why
I don't normally use sockets in the main thread to begin with.
|
Using blocking sockets virtually requires a background thread to
service the connection, but it doesn't scale well when you have many
sockets. Using non-blocking sockets works well in the main thread, as
it's also "event driven" though by a different mechanism than the main
VCL event loop.
Not that I'm advocating this, but it's a very viable alternative for
multi-threadding simply for the sake of getting around blocking socket
calls.
--
Chris (TeamB); |
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