sending structure in client server..

[swetha]

Hi ,
I want to send a structure (user defined) for example :

struct bank{

int empid;
char name[50];
float amount;

} per;

I want to send this from a client to server on unix.Can any1 tell me
how to send this(from client) and read the data at the other end(at
server).tnx in advance...

[vippstar]

On Oct 11, 7:18 pm, swetha <[e-mail]:

Hi ,
I want to send a structure (user defined) for example :

struct bank{

int empid;
char name[50];
float amount;

} per;

I want to send this from a client to server on unix.Can any1 tell me
how to send this(from client) and read the data at the other end(at
server).tnx in advance...

Ask in an appropriate newsgroup. <comp.unix.programmermight help
you.
Unix, networking et cetera are off-topic here in <comp.lang.cwhere
only the C language is discussed.

[Antoninus Twink]

On 11 Oct 2008 at 16:18, swetha wrote:

I want to send this from a client to server on unix.Can any1 tell me
how to send this(from client) and read the data at the other end(at
server).tnx in advance...

Assuming the client and server are both running on the same machine,
there are a wide variety of options available to you, and without
further information about your setup, it's hard to recommend one in
particular. For example, you could use named pipes, shared memory or
sockets. If the client and server are running on different machines,
you'll need to rely on the last of those options...

To find out more, "interprocess communication" or "IPC" would be a good
term to Google. If you want more guidance here, you'll need to describe
your application in more detail.

[Gordon Burditt]

I want to send a structure (user defined) for example :

You need to worry about whether that structure will be represented
the same on the client and the server. Different architectures use
different sizes for int and float, may use different endianness,
and use different padding. Even the same architecture running
different versions of the compiler might have these issues. It's
a problem if the client and server could be different.

You'll have the same issues whether the structure is sent in a file
copied from one machine to another, or over a network.

>struct bank{

int empid;
char name[50];
float amount;

} per;

I want to send this from a client to server on unix.Can any1 tell me
how to send this(from client) and read the data at the other end(at
server).tnx in advance...

[Keith Thompson]

Antoninus Twink <no****@nospam.invalidwrites:

On 11 Oct 2008 at 16:18, swetha wrote:

>I want to send this from a client to server on unix.Can any1 tell me
how to send this(from client) and read the data at the other end(at
server).tnx in advance...

[...]

>
To find out more, "interprocess communication" or "IPC" would be a good
term to Google. If you want more guidance here, you'll need to describe
your application in more detail.

If you want more guidance here, you'll be asking in the wrong place.
comp.unix.programmer is full of Unix experts, most of whom know more
about this stuff than most of the people here. "Antoninus Twink", for
whatever reason, apparently doesn't want you to know that.

--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[Malcolm McLean]

"swetha" <la*******@gmail.comwrote in message news:

Hi ,
I want to send a structure (user defined) for example :

struct bank{

int empid;
char name[50];
float amount;

} per;

I want to send this from a client to server on unix.Can any1 tell me
how to send this(from client) and read the data at the other end(at
server).tnx in advance...

write two functions

int serialise_bank(const struct bank *b, void *buff)

void deserialise_bank(struct bank *b, void *buff)

They turn the structure into a platform-independent packet of bytes. You can
use sprintf(buffer, "%.*f", FLT_DIG, b->amount) to serialise the float in
ascii, or you can break it up into sign, exponent and matissa and send it in
binary.
Similarly the integers need to be in big or little endian. Preferably
big-endian in case those little endians take over the world and make us all
store our ints at the little end.

Then just send the packet over the network

--
Free games and programming goodies.
http://www.personal.leeds.ac.uk/~bgy1mm

[Nick Keighley]

On Oct 11, 6:15*pm, Antoninus Twink <[e-mail]:

On 11 Oct 2008 at 16:18, swetha wrote:

I want to send this from a client to server on unix.Can any1 tell me
how to send this(from client) and read the data at the other end(at
server).tnx in advance...

Assuming the client and server are both running on the same machine,

isn't that a rather atypical Client Server application?
Yes, I know it happens but wouldn't it be more reasonable
to assume the Client and Server were on different machines.
Maybe utterly different hardware.

To the OP: try a Unix newsgroup and ask about sockets.

<snip>

--
Nick Keighley

[Antoninus Twink]

On 12 Oct 2008 at 19:58, Nick Keighley wrote:

On Oct 11, 6:15Â*pm, Antoninus Twink <[e-mail]:

>Assuming the client and server are both running on the same machine,

isn't that a rather atypical Client Server application?
Yes, I know it happens but wouldn't it be more reasonable
to assume the Client and Server were on different machines.

I'd hardly call it atypical. How many daemons are running on your
machine at the moment waiting for local connections? Are you running X
Windows at the moment with local client programs?

The OP didn't give us enough information to tell what his setup was: I
gave advice (which you snipped) that deals with both situations.

[Ian Collins]

Nick Keighley wrote:

>
To the OP: try a Unix newsgroup and ask about sockets.

He did, yesterday.

--
Ian Collins

[Ian Collins]

Antoninus Twink wrote:

On 12 Oct 2008 at 19:58, Nick Keighley wrote:

>On Oct 11, 6:15 pm, Antoninus Twink <[e-mail]:

>>Assuming the client and server are both running on the same machine,

isn't that a rather atypical Client Server application?
Yes, I know it happens but wouldn't it be more reasonable
to assume the Client and Server were on different machines.

I'd hardly call it atypical. How many daemons are running on your
machine at the moment waiting for local connections? Are you running X
Windows at the moment with local client programs?

Plenty and they also accept and correctly process remote ones. Fool.

--
Ian Collins

[Pietro Cerutti]

On Sat, 11 Oct 2008 20:42:04 +0100, Malcolm McLean wrote:

"swetha" <la*******@gmail.comwrote in message news:

>Hi ,
I want to send a structure (user defined) for example :

struct bank{

int empid;
char name[50];
float amount;

} per;

I want to send this from a client to server on unix.Can any1 tell me
how to send this(from client) and read the data at the other end(at
server).tnx in advance...

write two functions

int serialise_bank(const struct bank *b, void *buff)

void deserialise_bank(struct bank *b, void *buff)

They turn the structure into a platform-independent packet of bytes. You
can use sprintf(buffer, "%.*f", FLT_DIG, b->amount) to serialise the
float in ascii, or you can break it up into sign, exponent and matissa
and send it in binary.
Similarly the integers need to be in big or little endian. Preferably
big-endian in case those little endians take over the world and make us
all store our ints at the little end.

Or just use XDR and don't reinvent the weel :)

>
Then just send the packet over the network

--
Pietro Cerutti