如何以编程方式获取Linux中目录的可用磁盘空间

Question

是否有一个函数可以返回给定目录路径的驱动器分区上有多少可用空间？

Answer 1

校验 man statvfs(2)

我相信你可以计算出"自由空间" f_bsize * f_bfree.

NAME
       statvfs, fstatvfs - get file system statistics

SYNOPSIS
       #include <sys/statvfs.h>

       int statvfs(const char *path, struct statvfs *buf);
       int fstatvfs(int fd, struct statvfs *buf);

DESCRIPTION
       The function statvfs() returns information about a mounted file system.
       path is the pathname of any file within the mounted file  system.   buf
       is a pointer to a statvfs structure defined approximately as follows:

           struct statvfs {
               unsigned long  f_bsize;    /* file system block size */
               unsigned long  f_frsize;   /* fragment size */
               fsblkcnt_t     f_blocks;   /* size of fs in f_frsize units */
               fsblkcnt_t     f_bfree;    /* # free blocks */
               fsblkcnt_t     f_bavail;   /* # free blocks for unprivileged users */
               fsfilcnt_t     f_files;    /* # inodes */
               fsfilcnt_t     f_ffree;    /* # free inodes */
               fsfilcnt_t     f_favail;   /* # free inodes for unprivileged users */
               unsigned long  f_fsid;     /* file system ID */
               unsigned long  f_flag;     /* mount flags */
               unsigned long  f_namemax;  /* maximum filename length */
           };

Answer 2

你可以使用boost :: filesystem:

struct space_info  // returned by space function
{
    uintmax_t capacity;
    uintmax_t free; 
    uintmax_t available; // free space available to a non-privileged process
};

space_info   space(const path& p);
space_info   space(const path& p, system::error_code& ec);

例:

#include <boost/filesystem.hpp>
using namespace boost::filesystem;
space_info si = space(".");
cout << si.available << endl;

返回:类型为space_info的对象.space_info对象的值确定为使用POSIX statvfs()获取POSIX结构statvfs,然后将其f_blocks,f_bfree和f_bavail成员乘以其f_frsize成员,并将结果分配给容量,free和可用会员分别.任何无法确定其值的成员都应设置为-1.

Answer 3

使用 C++17

您可以使用std::filesystem::space：

#include <iostream>  // only needed for screen output

#include <filesystem>
namespace fs = std::filesystem;

int main()
{
    fs::space_info tmp = fs::space("/tmp");

    std::cout << "Free space: " << tmp.free << '\n'
              << "Available space: " << tmp.available << '\n';
}