Python and UDP sockets

[Zunbeltz Izaola]

Hi!

I want to port a small socket aplication (in C) to Python.
The server is writen in C, and it expected to recibe and C struct
like this


struct tag_instruccion
{
unsigned int Handle __attribute__ ((aligned(1)));
int Codigo __attribute__ ((aligned(1)));
double Param[10] __attribute__ ((aligned(1)));
char Comando[_MAX_PATH] __attribute__ ((aligned(1))) ;
char Instruc[_MAX_PATH] __attribute__ ((aligned(1))) ;
};

I know that the functions for sockets are essentialy those that are in
C (BSD sockets), but i don't know how to send this kind of struct
directly.

One of the function to send a socket is this

EnviaMensaje(SOCKET iSocket,int port,char *host, instruccion *Instruccion)
{
struct sockaddr_in siSockAddr;
int iRc;
CodigoMensaje resultado;

if (iSocket != INVALID_SOCKET)
{
memset((char *)&siSockAddr,0,sizeof(siSockAddr));
siSockAddr.sin_family = AF_INET;
siSockAddr.sin_port = htons(port);
siSockAddr.sin_addr.s_addr = inet_addr(host);
iRc = sendto(iSocket,(char const FAR *)Instruccion,sizeof(instruccion),0,(struct sockaddr FAR *)(&siSockAddr),sizeof(siSockAddr));
}
return iRc;
}

Can someone help me?
Thanks in advance

Zunbeltz Izaola

 

[Alex Martelli]

Zunbeltz Izaola wrote:
...

C (BSD sockets), but i don't know how to send this kind of struct
directly.

You transform the tuple of field values into a string with struct.pack
and send the string. And vv in receiving. See:

http://www.python.org/doc/current/lib/module-struct.html


Alex

 

[Werner Schiendl]

Hi,

look at the struct module from the python standard library.

in particular, struct.pack allows to format your data as required.

hth
Werner

 

[Zunbeltz Izaola]

Hi

Thanks for the point. I'm using struct and it is working well.
Thanks again

Zunbeltz

Hi,

look at the struct module from the python standard library.

in particular, struct.pack allows to format your data as required.

hth
Werner

Hi!
I want to port a small socket aplication (in C) to Python.
The server is writen in C, and it expected to recibe and C struct
like this struct tag_instruccion
{
unsigned int Handle __attribute__ ((aligned(1)));
int Codigo __attribute__ ((aligned(1)));
double Param[10] __attribute__ ((aligned(1)));
char Comando[_MAX_PATH] __attribute__ ((aligned(1))) ;
char Instruc[_MAX_PATH] __attribute__ ((aligned(1))) ;
};
I know that the functions for sockets are essentialy those that are
in
C (BSD sockets), but i don't know how to send this kind of struct
directly.
One of the function to send a socket is this
EnviaMensaje(SOCKET iSocket,int port,char *host, instruccion
*Instruccion)
{
struct sockaddr_in siSockAddr;
int iRc;
CodigoMensaje resultado;
if (iSocket != INVALID_SOCKET)
{
memset((char *)&siSockAddr,0,sizeof(siSockAddr));
siSockAddr.sin_family = AF_INET;
siSockAddr.sin_port = htons(port);
siSockAddr.sin_addr.s_addr = inet_addr(host);
iRc = sendto(iSocket,(char const FAR *)Instruccion,sizeof(instruccion),0,(struct sockaddr FAR *)(&siSockAddr),sizeof(siSockAddr));
}
return iRc;
}
Can someone help me?
Thanks in advance
Zunbeltz Izaola