statvfs.cpp

#include <iostream>
#include <string.h>
#include <sys/statvfs.h>

/*
 * How do we find disk usage?  You know, the way "df" does?  we can
 * use statvfs() or statfs() calls!  The former is moar standard and
 * POSIX-ey, the latter is BSD-ism that Linux happens to have
 * implemented.
 *
 * Results from the below code seems to be consistent with "df -i /"
 * and "df --block-size=<bs> /".
 */

int main(int argc, char *argv[])
{
    if (argc < 2)
    {
        std::cout << "Usage: " << argv[0] << " <path>" << std::endl;
        return 1;
    }

    struct statvfs s{0};

    if (statvfs(argv[1], &s) < 0)
    {
        std::cerr << "Error from statvfs(): " << strerror(errno) << std::endl;
        return 1;
    }

    std::cout << "f_bsize   : " << s.f_bsize   << std::endl; /* file system block size */
    std::cout << "f_frsize  : " << s.f_frsize  << std::endl; /* fragment size */
    std::cout << "f_blocks  : " << s.f_blocks  << std::endl; /* size of fs in f_frsize units */
    std::cout << "f_bfree   : " << s.f_bfree   << std::endl; /* # free blocks */
    std::cout << "f_bavail  : " << s.f_bavail  << std::endl; /* # free blocks for unprivileged users */
    std::cout << "f_files   : " << s.f_files   << std::endl; /* # inodes */
    std::cout << "f_ffree   : " << s.f_ffree   << std::endl; /* # free inodes */
    std::cout << "f_favail  : " << s.f_favail  << std::endl; /* # free inodes for unprivileged users */
    std::cout << "f_fsid    : " << s.f_fsid    << std::endl; /* file system ID */
    std::cout << "f_flag    : " << s.f_flag    << std::endl; /* mount flags */
    std::cout << "f_namemax : " << s.f_namemax << std::endl; /* maximum filename length */

    return 0;
}

// Local Variables:
// compile-command: "g++ -Wall -std=c++11 statvfs.cc -o statvfs"
// End: