VS2017 使用Unicode 字符集写的一个例子---获取磁盘标号，大小，使用情况。
GetDriveType
头文件在“winbase.h"
判断一个磁盘驱动器的类型，返回值long，如果不能识别，则返回0.若是指定目录不存在，则返回1，如执行成功，则用下述任何一个常数指定驱动器类型：DRIVE_REMOVABLE， DRIVE_FIXED， DRIVE_REMOTE， DRIVE_CDROM 或 DRIVE_RAMDISK
函数原型如下:
UINT GetDriveType(
LPCTSTR lpRootPathName // root directory
);
参数说明: lpRootPathName 包含了根目录路径的字符串指针
返回值
DRIVE_UNKNOWN 未知的磁盘类型
DRIVE_NO_ROOT_DIR 说明lpRootPathName是无效的
DRIVE_REMOVABLE 可移动磁盘
DRIVE_FIXED 固定磁盘
DRIVE_REMOTE 网络磁盘
DRIVE_CDROM 光驱
DRIVE_RAMDISK 为RAM
GetLogicalDriveStrings，获取一个字串，其中包含了当前所有逻辑驱动器的根驱动器路径。
函数原型如下：
DWORD GetLogicalDriveStrings(
DWORD nBufferLength,
LPTSTR lpBuffer);
参数：
nBufferLength: 指向的内存空间的大小，以字节为单位。
lpBuffer: 指向存储返回结果字符串的内存空间
返回值：
函数的返回值指明了函数调用是否成功，如果成功则返回缓冲区中返回结果的总长度；如果返回值大于nBufferLength，说明给定的缓冲区大小不够，返回值是实际需要的大小；如果返回0，则说明函数运行出错。
说明：
函数调用成功后，将在缓冲区中依次填入本机所具有的驱动器根路径字符串，假如系统中有4个逻辑驱动器“C:\”、“D:\”、“E:\”，“F:\”。执行后在缓冲区中的结果如下：
0x43 0x3a 0x5c 0x00 0x44 0x3a 0x5c 0x000x45 0x3a 0x5c 0x00 0x46 0x3a 0x5c 0x00 0x00即连续存放了“C:\”、“D:\”、“E:\”，“F:\”这4个字符串。
注意：会在每个字符串后加一个‘\0’结束符，在所有卷标字符串的最后在加一个结束符）。
GetDiskFreeSpaceEx
#ifdef UNICODE---GetDiskFreeSpaceExW
#else---GetDiskFreeSpaceExA
在vs中函数原型如下:
WINBASEAPI
BOOL
WINAPI
GetDiskFreeSpaceExA(
_In_opt_ LPCSTR lpDirectoryName,
_Out_opt_ PULARGE_INTEGER lpFreeBytesAvailableToCaller,
_Out_opt_ PULARGE_INTEGER lpTotalNumberOfBytes,
_Out_opt_ PULARGE_INTEGER lpTotalNumberOfFreeBytes
);WINBASEAPI
BOOL
WINAPI
GetDiskFreeSpaceExW(
_In_opt_ LPCWSTR lpDirectoryName,
_Out_opt_ PULARGE_INTEGER lpFreeBytesAvailableToCaller,
_Out_opt_ PULARGE_INTEGER lpTotalNumberOfBytes,
_Out_opt_ PULARGE_INTEGER lpTotalNumberOfFreeBytes
);lpDirectoryName是驱动器的名称。
lpFreeBytesAvailableToCaller是用户可用的磁盘空间。
lpTotalNumberOfBytes是磁盘总共的空间。
lpTotalNumberOfFreeBytes是磁盘空闲的空间。以上都是字节为单位。
. cpp
#include <iostream>
#include <windows.h>
#include <string.h>
#define GB(x) (x.HighPart << 2) + (x.LowPart >> 20) / 1024.0
using namespace std;
int main()
{
ULARGE_INTEGER freeBytesAvailableToCaller;
ULARGE_INTEGER totalNumberOfBytes;
ULARGE_INTEGER totalNumberOfFreeBytes;
int totalOfGB, freeOfGB, useOfGB;
string drive_cout, drive_index, total_size, free_size;
DWORD drive_info = GetLogicalDrives(); //获取主机中所有的逻辑驱动器字母，以BitMap的形式返回
char driver_info_buf[MAX_PATH] = { 0 };
_itoa_s(drive_info, driver_info_buf, 2);
int m_driverCount = 0;
while (drive_info)
{
if (drive_info & 1)
{
m_driverCount++;
}
drive_info >>= 1;
}
cout << "磁盘个数: " << m_driverCount << endl;
int drive_strLen = GetLogicalDriveStrings(0, NULL); //获取一个字串，其中包含了当前所有逻辑驱动器的根驱动器路径。
WCHAR *drive_str = new WCHAR[drive_strLen];
GetLogicalDriveStrings(drive_strLen, drive_str); //装载逻辑驱动器名称的字串到数组driveStr
for (int i = 0; i < m_driverCount; i++)
{
UINT driveType = GetDriveType(drive_str);
GetDiskFreeSpaceEx(drive_str, &freeBytesAvailableToCaller, &totalNumberOfBytes, &totalNumberOfFreeBytes);
if (driveType != DRIVE_FIXED) //固定磁盘
return 0;
string disk_name((const char*)drive_str);
drive_index = disk_name.substr(0, 2);
totalOfGB = GB(totalNumberOfBytes);
freeOfGB = GB(totalNumberOfFreeBytes);
useOfGB = totalOfGB - freeOfGB;
cout << "磁盘 " << drive_index.c_str() << " 总大小: " << totalOfGB << " GB 可用空间: " << freeOfGB << " GB 已使用: " << useOfGB << " GB" << endl;
drive_str += 4;
}
return 0;
}方法二
GlobalMemoryStatusEx函数用于获取系统内存信息：
BOOL WINAPI GlobalMemoryStatusEx(
__inout LPMEMORYSTATUSEX lpBuffer
);
// Sample output:
// There is 51 percent of memory in use.
// There are 2029968 total KB of physical memory.
// There are 987388 free KB of physical memory.
// There are 3884620 total KB of paging file.
// There are 2799776 free KB of paging file.
// There are 2097024 total KB of virtual memory.
// There are 2084876 free KB of virtual memory.
// There are 0 free KB of extended memory.
#include <windows.h>
#include <stdio.h>
#include <tchar.h>
// Use to convert bytes to KB
#define DIV 1024
// Specify the width of the field in which to print the numbers.
// The asterisk in the format specifier "%*I64d" takes an integer
// argument and uses it to pad and right justify the number.
#define WIDTH 7
void _tmain()
{
MEMORYSTATUSEX statex;
statex.dwLength = sizeof (statex);
GlobalMemoryStatusEx (&statex);
_tprintf (TEXT("There is %*ld percent of memory in use.\n"),
WIDTH, statex.dwMemoryLoad);
_tprintf (TEXT("There are %*I64d total KB of physical memory.\n"),
WIDTH, statex.ullTotalPhys/DIV);
_tprintf (TEXT("There are %*I64d free KB of physical memory.\n"),
WIDTH, statex.ullAvailPhys/DIV);
_tprintf (TEXT("There are %*I64d total KB of paging file.\n"),
WIDTH, statex.ullTotalPageFile/DIV);
_tprintf (TEXT("There are %*I64d free KB of paging file.\n"),
WIDTH, statex.ullAvailPageFile/DIV);
_tprintf (TEXT("There are %*I64d total KB of virtual memory.\n"),
WIDTH, statex.ullTotalVirtual/DIV);
_tprintf (TEXT("There are %*I64d free KB of virtual memory.\n"),
WIDTH, statex.ullAvailVirtual/DIV);
// Show the amount of extended memory available.
_tprintf (TEXT("There are %*I64d free KB of extended memory.\n"),
WIDTH, statex.ullAvailExtendedVirtual/DIV);
}方法二借鉴于MSDN：https://docs.microsoft.com/zh-cn/windows/desktop/api/sysinfoapi/nf-sysinfoapi-globalmemorystatusex