gettype.c

实战的linux socket编程--示例源码

/* gettype.c:
 * 
 * Get SO_TYPE Option :
 */
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <assert.h>

/*
 * This function reports the error and
 * exits back to the shell :
 */
static void
bail(const char *on_what) {
    if ( errno != 0 ) {
        fputs(strerror(errno),stderr);
        fputs(": ",stderr);
    }
    fputs(on_what,stderr);
    fputc('\n',stderr);
    exit(1);
}

int
main(int argc,char **argv) {
    int z;
    int s = -1;               /* Socket */
    int so_type = -1;    /* Socket type */
    socklen_t optlen;  /* Option length */

    /*
     * Create a TDP/IP socket to use :
     */
    s = socket(PF_INET,SOCK_STREAM,0);
    if ( s == -1 )
        bail("socket(2)");

    /*
     * Get socket option SO_SNDBUF :
     */
    optlen = sizeof so_type;
    z = getsockopt(s,SOL_SOCKET,SO_TYPE,
        &so_type,&optlen);
    if ( z )
        bail("getsockopt(s,SOL_SOCKET,"
            "SO_TYPE)");

    assert(optlen == sizeof so_type);

    /*
     * Report the buffer sizes :
     */
    printf("Socket s : %d\n",s);
    printf(" SO_TYPE : %d\n",so_type);
    printf(" SOCK_STREAM = %d\n",
        SOCK_STREAM);

    close(s);
    return 0;
}