Question

为了与BLE设备通信，我在Linux OS上使用了Bluez库。但是当我运行我的代码时，有时我在连接设备时收到了失败状态。请看这个功能：

static int l2cap_le_att_connect(bdaddr_t *src, bdaddr_t *dst, uint8_t dst_type,
                                    int sec)
{
    int sock;
    struct sockaddr_l2 srcaddr, dstaddr;
    struct bt_security btsec;

    if (verbose) {
        char srcaddr_str[18], dstaddr_str[18];

        ba2str(src, srcaddr_str);
        ba2str(dst, dstaddr_str);

        printf("btgatt-client: Opening L2CAP LE connection on ATT "
                    "channel:\n\t src: %s\n\tdest: %s\n",
                    srcaddr_str, dstaddr_str);
    }

    sock = socket(PF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_L2CAP);
    if (sock < 0) {
        perror("Failed to create L2CAP socket");
        return -1;
    }

    /* Set up source address */
    memset(&srcaddr, 0, sizeof(srcaddr));
    srcaddr.l2_family = AF_BLUETOOTH;
    srcaddr.l2_cid = htobs(ATT_CID);
    srcaddr.l2_bdaddr_type = 0;
    bacpy(&srcaddr.l2_bdaddr, src);

    if (bind(sock, (struct sockaddr *)&srcaddr, sizeof(srcaddr)) < 0) {
        perror("Failed to bind L2CAP socket");
        close(sock);
        return -1;
    }

    /* Set the security level */
    memset(&btsec, 0, sizeof(btsec));
    btsec.level = sec;
    if (setsockopt(sock, SOL_BLUETOOTH, BT_SECURITY, &btsec,
                            sizeof(btsec)) != 0) {
        fprintf(stderr, "Failed to set L2CAP security level\n");
        close(sock);
        return -1;
    }

    /* Set up destination address */
    memset(&dstaddr, 0, sizeof(dstaddr));
    dstaddr.l2_family = AF_BLUETOOTH;
    dstaddr.l2_cid = htobs(ATT_CID);
    dstaddr.l2_bdaddr_type = dst_type;
    bacpy(&dstaddr.l2_bdaddr, dst);

    printf("Connecting to device...");
    fflush(stdout);

    if (connect(sock, (struct sockaddr *) &dstaddr, sizeof(dstaddr)) < 0) {
        perror(" Failed to connect");
        close(sock);
        return -1;
    }

    printf(" Done\n");

    return sock;
}

问题是，connect（）函数返回-1，而errno是EMLINK 我读了很多文件，但我找不到这个bug的原因。请帮我。谢谢

Answer 1

Linux内核映射蓝牙error code 0x9 to EMLINK。蓝牙错误0x9表示＆＃34;连接太多＆＃34;。也许您的设备不支持这类连接，或者在您尝试打开太多连接时，现在仍然认为它们仍然存在。

免责声明，我不是蓝牙专家。

使用connect（）函数时收到错误的EMLINK

1 个答案: