Les sockets et les processus

/*
* Calls gethostbyname and getservbyname and fills in a struct addr_in.
* Prints host IP address in dotted notation and as an int (network order
* and machine order) and the port number.
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#if defined( LINUX )
#include <string.h>
#endif
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
int main( int argc, char **argv ) {
struct hostent *host;
struct servent *serv;
struct sockaddr_in addr;
char *hostname;
char *servname;
char *protname;
switch ( argc ) {
case 4:
hostname = argv[1];
servname = argv[2];
protname = argv[3];
break;
default:
usage: fprintf( stderr, "%s hostname servname proto\n", argv[0] );
exit( 1 );
}
if ( (serv = getservbyname( servname, protname )) == 0 ) {
fprintf( stderr, "Service not found\n" ); /* errno == 0 ! */
return -1;
}
endservent();
if ( (host = gethostbyname( hostname )) == 0 ) {
fprintf( stderr, "Host not found\n" ); /* errno == 0 ! */
return -1;
}
endhostent();
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = *((unsigned *) host->h_addr);
addr.sin_port = serv->s_port; /* already in network order */
printf( "%u.%u.%u.%u 0x%x (0x%x) %d (%d)\n", ((unsigned char *) &addr.sin_addr.s_addr)[0],
((unsigned char *) &addr.sin_addr.s_addr)[1], ((unsigned char *) &addr.sin_addr.s_addr)[2],
((unsigned char *) &addr.sin_addr.s_addr)[3],
addr.sin_addr.s_addr, /* network order */
ntohl( addr.sin_addr.s_addr ), /* machine order */
addr.sin_port, /* network order */
ntohs( addr.sin_port ) ); /* machine order */
exit( 0 );
}

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