getsndrcv.c

实战Linux socket编程例题源代码

/* getsndrcv.c:
 * 
 * Get SO_SNDBUF & SO_RCVBUF Options :
 */
#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 sndbuf=0;   /* Send buffer size */
    int rcvbuf=0;/* Receive buffer size */
    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 sndbuf;
    z = getsockopt(s,SOL_SOCKET,SO_SNDBUF,
        &sndbuf,&optlen);
    if ( z )
        bail("getsockopt(s,SOL_SOCKET,"
            "SO_SNDBUF)");

    assert(optlen == sizeof sndbuf);

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

    assert(optlen == sizeof rcvbuf);

    /*
     * Report the buffer sizes :
     */
    printf("Socket s : %d\n",s);
    printf(" Send buf: %d bytes\n",
        sndbuf);
    printf(" Recv buf: %d bytes\n",
        rcvbuf);

    close(s);
    return 0;
}