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std::filesystem::space_info

From cppreference.com
< cpp‎ | filesystem
 
 
Filesystem library
 
Defined in header <filesystem>
struct space_info {

    std::uintmax_t capacity;
    std::uintmax_t free;
    std::uintmax_t available;

};
(since C++17)

Represents the filesystem information as determined by filesystem::space.

[edit] Member objects

capacity
total size of the filesystem, in bytes
(public member object)
free
free space on the filesystem, in bytes
(public member object)
available
free space available to a non-privileged process (may be equal or less than free)
(public member object)

[edit] Non-member functions

operator==
(C++20)
compares two space_infos
(function)

operator==(std::filesystem::space_info)

friend bool operator==( const space_info&, const space_info& ) = default;
(since C++20)

Checks if capacity, free and available of both arguments are equal respectively.

This function is not visible to ordinary unqualified or qualified lookup, and can only be found by argument-dependent lookup when std::filesystem::space_info is an associated class of the arguments.

The != operator is synthesized from operator==.

[edit] Example

Run this code
#include <cstdint>
#include <filesystem>
#include <iostream>
#include <locale>
 
std::uintmax_t disk_usage_percent(const std::filesystem::space_info& si,
 bool is_privileged = false) noexcept
{
 if (constexpr std::uintmax_t X(-1);
 si.capacity == 0 || si.free == 0 || si.available == 0 ||
 si.capacity == X || si.free == X || si.available == X
 )
 return 100;
 
 std::uintmax_t unused_space = si.free, capacity = si.capacity;
 if (!is_privileged)
 {
 const std::uintmax_t privileged_only_space = si.free - si.available;
 unused_space -= privileged_only_space;
 capacity -= privileged_only_space;
 }
 const std::uintmax_t used_space{capacity - unused_space};
 return 100 * used_space / capacity;
}
 
void print_disk_space_info(auto const& dirs, int width = 14)
{
 (std::cout << std::left ).imbue(std::locale ("en_US.UTF-8"));
 
 for (const auto s : {"Capacity", "Free", "Available", "Use%", "Dir"})
 std::cout << "│ " << std::setw (width) << s << ' ';
 
 for (std::cout << '\n'; auto const& dir : dirs)
 {
 std::error_code ec;
 const std::filesystem::space_info si = std::filesystem::space (dir, ec);
 for (auto x : {si.capacity, si.free, si.available, disk_usage_percent(si)})
 std::cout << "│ " << std::setw (width) << static_cast<std::intmax_t >(x) << ' ';
 std::cout << "│ " << dir << '\n';
 }
}
 
int main()
{
 const auto dirs = {"/dev/null", "/tmp", "/home", "/proc", "/null"};
 print_disk_space_info(dirs);
}

Possible output:

│ Capacity │ Free │ Available │ Use% │ Dir 
│ 84,417,331,200 │ 42,732,986,368 │ 40,156,028,928 │ 50 │ /dev/null
│ 84,417,331,200 │ 42,732,986,368 │ 40,156,028,928 │ 50 │ /tmp
│ -1 │ -1 │ -1 │ 100 │ /home
│ 0 │ 0 │ 0 │ 100 │ /proc
│ -1 │ -1 │ -1 │ 100 │ /null

[edit] See also

(C++17)
determines available free space on the file system
(function) [edit]
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