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[lwip-users] [lwip] Date: Mon, 4 Mar 2002 19:52:15 +0500
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From: |
Muhammad Ashraf |
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Subject: |
[lwip-users] [lwip] Date: Mon, 4 Mar 2002 19:52:15 +0500 |
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Date: |
Thu, 09 Jan 2003 02:11:22 -0000 |
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In function tcp_enqueue
when copy flag is not set and option field is null , then these two =
conditions are false=20
if(optdata !=3D NULL) {
and=20
} else if(copy) {
In the else case=20
It firstly allocate the memory for the (pbuf) type struct called p of =
type PBUF_ROM.Its p-payload points to the application data.
Now again memory is allocated for=20
TCP + IP + DATALINKHEADER
is assighn to seg->p=20
under the type of PBUF_RAM
After that seg->p and p are chained where seg->p->next points to p.Now p =
is a structure whose p->payload contain only=20
application data.
I cant understand the purpose of this whole and what is its advantage.
Where this can be done by using a single struct.
Can any body explain .
Regards
ashraf
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<META content=3D"text/html; charset=3Diso-8859-1" =
http-equiv=3DContent-Type>
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<DIV><FONT face=3DArial size=3D2>In function tcp_enqueue</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>when copy flag is not set and option =
field is null=20
, then these two conditions are false </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2> if(optdata !=3D NULL) =
{<BR></FONT></DIV>
<DIV><FONT face=3DArial size=3D2>and </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2> } else if(copy)=20
{<BR></FONT></DIV>
<DIV><FONT face=3DArial size=3D2>In the else case </FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>It firstly allocate the memory for the =
(pbuf) =20
type struct called p of type PBUF_ROM.Its =
p-payload =20
points to the application data.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Now again memory is allocated for=20
</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2> =20
TCP + IP +=20
DATALINKHEADER</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>is assighn to seg->p </FONT></DIV>
<DIV><FONT face=3DArial size=3D2> =20
=
=20
under the type =
of=20
PBUF_RAM</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>After that seg->p and p are chained =
where=20
seg->p->next points to p.Now p is a structure whose p->payload =
contain=20
only </FONT></DIV>
<DIV><FONT face=3DArial size=3D2>application data.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I cant understand the purpose of this =
whole and=20
what is its advantage.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Where this can be done by using a =
single=20
struct.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>Can any body explain .</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>Regards</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>ashraf</FONT></DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2> </DIV></FONT></BODY></HTML>
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