Re: Socket programming

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Dear Ardhan,

We need to allocate the bar->name manually in general.

About the related socket programming issues, I recommend you one book.
UNIX Network Programming, Volume 1, Second Edition: Networking APIs:
Sockets and XTI, Prentice Hall, 1998, ISBN 0-13-490012-X.

Best regards,
Canaan

On Sun, Mar 22, 2009 at 9:31 PM, Ardhan Madras <ajhwb@xxxxxxxx> wrote:
> Dear Canaan,
>
> Thanks for your reply. It's a great clue :)
> btw, i have one more question...
>
> In the receiver, do i need to allocate for example
> bar->name member manually? or it's done by recv() ?
>
>
> --- canaan.kao@xxxxxxxxx wrote:
>
> From:   Canaan Kao <canaan.kao@xxxxxxxxx>
> To:     ajhwb@xxxxxxxx
> Cc:     linux-c-programming@xxxxxxxxxxxxxxx
> Subject: Re: Socket programming
> Date:   Sun, 22 Mar 2009 21:00:14 +0800
>
> Dear Ardhan,
>
> You can add a mySize data member in struct foo.
>
> struct foo
>  {
>  unsigned mySize;
>  char *name;
>  char *pix;
>  int id;
>  };
>
>
>  struct foo *bar = malloc (sizeof(struct foo));
>
>  if(NULL!=bar)bar->mySize=sizeof(struct foo);
>
>  /* fill the structure, then send */
>
> Finally, your receiver will get the size of foo in the beginning of the stream.
>
> Best regards,
> Canaan
>
> On Sun, Mar 22, 2009 at 8:42 PM, Ardhan Madras <ajhwb@xxxxxxxx> wrote:
>> Hi All,
>>
>> I was written small network utility in Linux 2.6, glibc 2.7.
>> I have been using send() and recv() system call in SOCK_STREAM
>> to send or receive fixed size data. for example, i write my data
>> structure like this:
>>
>> struct foo
>> {
>>  char name[16];
>>  char pix[1024];
>>  int id;
>> } bar;
>>
>> If i want to send or receive data i just call
>>
>> send (socket, &bar, sizeof(struct foo), 0);
>>
>> or to receive:
>> recv (socket, &bar, sizeof(struct foo), 0);
>>
>> My problem is how to receive dynamic sized data? for
>> example this structure:
>>
>> struct foo
>> {
>>  char *name;
>>  char *pix;
>>  int id;
>> }
>>
>> struct foo *bar = malloc (sizeof(struct foo));
>> /* fill the structure, then send */
>>
>> How to receive the data? since there are no way
>> to the receiver to know data sizes?
>>
>> Thanks for your help.
>>
>>
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>
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