tcp socket program puzzle

if i understand you right, you cannot define a buffer, which is big enough; for example:

char buffer;

so if i'm right you should try to use the malloc function ; in this case (*EDIT* for buffers greater than 1MB) you need to enable a kernel option to do so (for big portions of memory):

Processor type and features --> Allow allocating large blocks....

Greets

helmchen

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originally posted by helmchen@Jan 23 2007, 05:10 PM

if i understand you right, you cannot define a buffer, which is big enough; for example:

char buffer;

so if i'm right you should try to use the malloc function ; in this case (*edit* for buffers greater than 1mb) you need to enable a kernel option to do so (for big portions of memory):

processor type and features --> allow allocating large blocks....

greets

helmchen

<div align='right'><{post_snapback}> (index.php?act=findpost&pid=20794)</div>

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Thank you helmchen, you have understand me right.

Can I ask two more questions?

1, I have seen the option in the configure interface, but I wonder the kernel take use of what for the large blocks?

2, Can I just use the limited buffer to carry out large data transmission? For example, send several times?(I have tested, but still can&#39;t find good methods..)

Thanks again http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/smile.gif

<div class='quotetop'>QUOTE </div>

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1, I have seen the option in the configure interface, but I wonder the kernel take use of what for the large blocks?[/b]

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well i&#39;m not a kernel crack. Maybe you take a look at

http://www.linuxdevices.com/articles/at7777470166.html (http://www.linuxdevices.com/articles/at7777470166.html) and in the kernel docs.

Maybe someone else can explain it in short.

<div class='quotetop'>QUOTE </div>

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Can I just use the limited buffer to carry out large data transmission? For example, send several times?(I have tested, but still can&#39;t find good methods..[/b]

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you can reuse your buffers...

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Can I just use the limited buffer to carry out large data transmission? For example, send several times?(I have tested, but still can&#39;t find good methods..

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you can reuse your buffers...

<div align='right'><{post_snapback}> (index.php?act=findpost&pid=20816)</div>

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Thanks again, kind helmchen.

I have tried to reuse the buffers, for example, server send two times and client receive two times. But the result is not right..

I only found a method that is(TCP):

After send and receive once, client close the connection. And then establish another connetion and perform another transmition..

So in this way, If I need reuse my buffer ten times to finish the transmition, I have to establish and close the connection ten times..

Below is a segment of the client program to help you understand me.

----------------------------------------------------------------------

//The first connection, receive 1500 bytes

sockfd = socket(AF_INET,SOCK_STREAM,0);

bzero((struct sockaddr*)&serveraddr,sizeof(serveraddr));

serveraddr.sin_family=AF_INET;

serveraddr.sin_port=htons(5000);

inet_pton(AF_INET,argv[1],&(serveraddr.sin_addr));

if((connect(sockfd,((struct sockaddr*)&serveraddr),sizeof(serveraddr)))<0)

printf("connect error!!\n");

recvbyte=recv(sockfd,recvbuff,1500,0);

printf("recvbyte1=%d\n",recvbyte);

close(sockfd);

//The second connection,receive 1500 bytes.

sockfd = socket(AF_INET,SOCK_STREAM,0);

bzero((struct sockaddr*)&serveraddr,sizeof(serveraddr));

serveraddr.sin_family=AF_INET;

serveraddr.sin_port=htons(5000);

inet_pton(AF_INET,argv[1],&(serveraddr.sin_addr));

if((connect(sockfd,((struct sockaddr*)&serveraddr),sizeof(serveraddr)))<0)

printf("connect error!!\n");

recvbyte=recv(sockfd,recvbuff,1500,0);

printf("recvbyte2=%d\n",recvbyte);

close(sockfd);

...

---------------------------------------------------------------------

I think it&#39;s not a good way, so I am searching the good ways to reuse buffer. Do you have any good suggestions?

maybe you can also post the code for sending?

the receiving code looks good for me.