std::filesystem::space_info
From cppreference.com
< cpp | filesystem
| 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.
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) |
Non-member functions
(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==.
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
See also
(C++17) |
determines available free space on the file system (function) |