std::filesystem::space - cppreference.com (original) (raw)

Determines the information about the filesystem on which the pathname p is located, as if by POSIX statvfs.

Populates and returns an object of type filesystem::space_info, set from the members of the POSIX struct statvfs as follows:

• space_info.capacity is set as if by f_blocks * f_frsize.
• space_info.free is set to f_bfree * f_frsize.
• space_info.available is set to f_bavail * f_frsize.
• Any member that could not be determined is set to static_cast<std::uintmax_t>(-1).

The non-throwing overload sets all members to static_cast<std::uintmax_t>(-1) on error.

[edit] Parameters

[edit] Return value

The filesystem information (a filesystem::space_info object).

[edit] Exceptions

Any overload not marked noexcept may throw std::bad_alloc if memory allocation fails.

1. Throws std::filesystem::filesystem_error on underlying OS API errors, constructed with p as the first path argument and the OS error code as the error code argument.

2. Sets a std::error_code& parameter to the OS API error code if an OS API call fails, and executes ec.clear() if no errors occur.

[edit] Notes

space_info.available may be less than space_info.free.

[edit] Example

#include #include #include #include   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

| | information about free and available space on the filesystem (class) [edit] | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |