使用Netapi32库获取网络统计的C语言代码异常求助

我想用C语言获取网络统计信息，但调用NetStatisticsGet()函数后，返回状态显示成功，可每次打印缓冲区内容基本一致。单独打印结构体字段时，只有SmbsTransmitted字段每次循环递增1，UseCount、StatisticsStartTime、BytesReceived、BytesTransmitted字段有非零值但始终不变，其余字段全为0。查阅Windows官方文档未找到有效解决方法，求排查问题原因。

完整代码 #

#include <stdio.h>
#include <windows.h>
#include <lmstats.h>
#include <lmapibuf.h>

NET_API_STATUS status;
LPWSTR lpwsn = L"LanmanWorkstation";
LPBYTE lpBuf;
DWORD dwSize = 0;

int main() {
    while (1) {
        /* Print network stats at 500 ms intervals */
        status = NetStatisticsGet(NULL, lpwsn, 0, 0, &lpBuf);
        printf("lpbuf: %p\n", lpBuf);

        if (status == NERR_Success) {
            LPSTAT_WORKSTATION_0 pStats = (LPSTAT_WORKSTATION_0)lpBuf;
            NetApiBufferSize (lpBuf, &dwSize);

            for (int i = 0; i < dwSize; i++) printf("%02x", lpBuf[i]);
            printf("\n\n");
            
        } else {
            printf("status code %d\n", status);
            return 0;
        }
        Sleep(500);
    }
    NetApiBufferFree(lpBuf);
    return 0;
}

编译命令 #

gcc netstats.c -lNetapi32

输出结果 #

lpbuf: 0000025805c75660
432e32876ce0d901307f080000000000850200000000000000000000000000000000000000000000000000000000000000000000000000009e3d08000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000340000000000000000000000000000004c4d454dd800000038d08401f67f00000000000000000000

lpbuf: 0000025805c74000
432e32876ce0d901307f080000000000860200000000000000000000000000000000000000000000000000000000000000000000000000009e3d08000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000340000000000000000000000000000004c4d454dd800000038d08401f67f00000000000000000000

lpbuf: 0000025805c76160
432e32876ce0d901307f080000000000870200000000000000000000000000000000000000000000000000000000000000000000000000009e3d0800000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000340000000000000000000000000000004c4d454dd800000038d08401f67f00000000000000000000

lpbuf: 0000025805c768d0
432e32876ce0d901307f080000000000880200000000000000000000000000000000000000000000000000000000000000000000000000009e3d0800000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000340000000000000000000000000000004c4d454dd800000038d08401f67f00000000000000000000

问题分析及修复方案 #

核心问题 #

1. 内存泄漏+旧数据缓存：循环中每次调用NetStatisticsGet()都会分配新缓冲区，但从未调用NetApiBufferFree()释放，系统可能因资源限制返回缓存的旧统计数据，同时造成内存泄漏。
2. 参数错误：NetStatisticsGet()的第四个参数（dwReserved）传0不符合工作站统计的要求，需指定为STAT_WORKSTATION才能获取实时有效数据。
3. 调试方式低效：直接打印二进制缓冲区难以定位问题，应打印结构体具体字段值来验证数据更新情况。

修复后的代码 #

#include <stdio.h>
#include <windows.h>
#include <lmstats.h>
#include <lmapibuf.h>

int main() {
    NET_API_STATUS status;
    LPWSTR lpwsn = L"LanmanWorkstation";
    LPBYTE lpBuf = NULL;

    while (1) {
        // 指定STAT_WORKSTATION参数，确保获取实时工作站统计数据
        status = NetStatisticsGet(NULL, lpwsn, 0, STAT_WORKSTATION, &lpBuf);

        if (status == NERR_Success) {
            LPSTAT_WORKSTATION_0 pStats = (LPSTAT_WORKSTATION_0)lpBuf;
            printf("=== 网络统计快照 ===\n");
            printf("SMB发送数: %lu\n", pStats->work_station_0_smbs_transmitted);
            printf("接收字节数: %lu\n", pStats->work_station_0_bytes_received);
            printf("发送字节数: %lu\n", pStats->work_station_0_bytes_transmitted);
            printf("连接计数: %lu\n", pStats->work_station_0_use_count);
            printf("-------------------\n\n");
            
            // 每次循环后释放缓冲区，避免内存泄漏和旧数据缓存
            NetApiBufferFree(lpBuf);
            lpBuf = NULL;
        } else {
            printf("调用失败，错误码: %d\n", status);
            if (lpBuf != NULL) {
                NetApiBufferFree(lpBuf);
            }
            return 1;
        }
        Sleep(500);
    }
    return 0;
}

额外说明 #

• 若需要更详细的统计数据，可将NetStatisticsGet()的第三个参数（level）设为1，获取STAT_WORKSTATION_1结构体，该结构体包含更多网络统计字段。
• NetStatisticsGet()针对不同服务（如LanmanWorkstation、LanmanServer）有不同的参数要求，需根据目标服务选择对应的统计类型标识。

内容的提问来源于stack exchange，提问作者vibhav950