Re: [Dev-C++] Sockets API - Newbie - send() function

[Peter D. <don...@ne...>]

Hi Daniel,

So 0 means there are no flags?  This is also from MSDN:

The send 
<http://msdn.microsoft.com/library/en-us/winsock/winsock/send_2.asp> and 
recv 
<http://msdn.microsoft.com/library/en-us/winsock/winsock/recv_2.asp> 
functions both return an integer value of the number of bytes sent or 
received, respectively, or an error. Each function also takes the same 
parameters: the active socket, a char buffer, the number of bytes to 
send or receive, and any flags to use.

 From the man page:
The  flags parameter is the bitwise OR of zero or more of the following 
flags.  So if you use 0 does this mean there are no flags?  But if i use 
one of the flags such as MSG_OOB then I take it the bitwise OR of 
MSG_OOB is not equal to 0?  For that matter is the bitwise of 0 equal to 0?

Is this right?

In the ballpark?

Or am I still on my own planet?

Thanks for your help,

Peter.


Daniel K. O. wrote:

> Peter Dennis wrote:
>
>> sent = send( datasock, string, strlen( string ), 0);
>>
>> I understand the first 3 parameters but can someone tell me what the 
>> '0' is as the fourth parameter to the send function?  (it is probably 
>> a flag but what does it do?  does it mean there are no flags?)
>
>
>
> You can find Winsock documentation at MSDN; you can also Google for a 
> .hlp/.chm help file for off-line reference.
> This is from 
> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winsock/winsock/send_2.asp 
> :
>
> ---
> int send(
>  SOCKET s,
>  const char* buf,
>  int len,
>  int flags
> );
>
> Parameters
>
> s
>    [in] Descriptor identifying a connected socket.
> buf
>    [in] Buffer containing the data to be transmitted.
> len
>    [in] Length of the data in buf, in bytes.
> flags
>    [in] Indicator specifying the way in which the call is made.
>
>
> (...)
>
>
> The flags parameter can be used to influence the behavior of the 
> function beyond the options specified for the associated socket. The 
> semantics of this function are determined by the socket options and 
> the flags parameter. The latter is constructed by using the bitwise OR 
> operator with any of the following values.
>
> MSG_DONTROUTE     Specifies that the data should not be subject to 
> routing. A Windows Sockets service provider can choose to ignore this 
> flag.
> MSG_OOB     Sends OOB data (stream-style socket such as SOCK_STREAM only.
> ---
>
>
> Daniel K. O.
>
>